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Hindawi Publishing Corporation Organic Chemistry International Volume 2013, Article ID 348379, 14 pages http://dx.doi.org/10.1155/2013/348379 Research Article Molecular Structure and Vibrational Spectra of 2-Ethylhexyl Acrylate by Density Functional Theory Calculations Ottman Belaidi, 1 Tewfik Bouchaour, 1 and Ulrich Maschke 2 1 Laboratoire de Recherche sur les Macromol´ ecules, Facult´ e des Sciences, Universit´ e Abou Bekr Belkaid, BP 119-13000, Tlemcen, Algeria 2 UMET (Unit´ e Mat´ eriaux et Transformations), UMR CNRS No. 8207, Universit´ e Lille 1-Sciences et Technologies, 59655 Villeneuve d’Ascq Cedex, France Correspondence should be addressed to Ottman Belaidi; [email protected] Received 26 February 2013; Accepted 28 April 2013 Academic Editor: Dipakranjan Mal Copyright © 2013 Ottman Belaidi et al. is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. e Fourier transform infrared spectra (FTIR) of 2-ethylhexyl acrylate have been measured in liquid phase. e molecular geometry, vibrational frequencies, and infrared intensities have been calculated by using density functional theory. We found two local minima representing s-cis and s-trans conformations for 2-ethylhexyl acrylate molecule. e optimized geometries at DFT//B3LYP/6-311+G ∗∗ are in good agreement with electron diffraction data of methyl acrylate for the acrylic group. e two conformers were used for the interpretation of the experimental infrared spectrum of title compound. PED calculations are represented for a more complete and concise assignment. ere is one band in the infrared spectrum at 1646 cm −1 that definitely indicates the conformer with s-trans arrangement of acrylic moiety to be present or not in the liquid 2-ethylhexyl acrylate. 1. Introduction Alkyl acrylates are important monomers used in the manu- facture of polymers and copolymers. Acrylates give polymers exhibiting outstanding transparency and aging proprieties which have made them of interest in a wide variety of applications [1–4]. e structural data and the preferred molecular conformation of these acrylates molecules would be important for basic understanding of these polymers [5]. 2-Ethylhexyl acrylate is used for production of paint, adhesive, and paper coating trade. is monomer imparts flexibility and water resistance to the polymers [1, 6]. It is also used for curing polymeric materials [7–15]. To our best knowledge no structural data or detailed interpretation of the vibrational spectra of 2-ethylhexyl acry- late is presented in the literature. is prompted us to look into the vibrational spectroscopy of 2-ethylhexyl acrylate more carefully. Many reports, experimental [16–21] and theoretical [20, 22], show that acrylates and related compounds exhibit rotational isomerism with the planar s-trans and s-cis heavy- atom structures being the energetically most stable confor- mations. However, uncertainty continues to exist regarding the relative stability of the two conformers. Gas electron diffraction studies on methyl methacrylate [20] suggested the cis/trans ratios to be equal to 2 : 1. On the other hand, the IR spectrum of methyl methacrylate in Ar low temperature matrix suggested an inverse ratio [23]. Many experimental and theoretical studies on methyl acrylate reported that the s-cis conformer is more stable than the s-trans conformer [24–29]. However, Bowles et al. [30] assumed that the s-trans conformer is more stable. 2. Experimental 2-Ethylhexyl acrylate (purity greater than 99%) was pur- chased from Sigma-Aldrich and it was used as it is without further purification. e infrared spectra of liquid films placed between the KBR windows were recorded within 4000–700 cm −1 range with a Perkin Elmer FTIR System-2000 model. 3. Computational e optimizations of the stable conformers were conducted with the density functional theory using 6-311+G ∗∗ basis

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Page 1: Research Article Molecular Structure and Vibrational Spectra ...e molecular geometry, vibrational frequencies, and infrared intensities have been calculated by using density functional

Hindawi Publishing CorporationOrganic Chemistry InternationalVolume 2013 Article ID 348379 14 pageshttpdxdoiorg1011552013348379

Research ArticleMolecular Structure and Vibrational Spectra of 2-EthylhexylAcrylate by Density Functional Theory Calculations

Ottman Belaidi1 Tewfik Bouchaour1 and Ulrich Maschke2

1 Laboratoire de Recherche sur les Macromolecules Faculte des Sciences Universite Abou Bekr Belkaid BP 119-13000 Tlemcen Algeria2 UMET (Unite Materiaux et Transformations) UMR CNRS No 8207 Universite Lille 1-Sciences et Technologies59655 Villeneuve drsquoAscq Cedex France

Correspondence should be addressed to Ottman Belaidi othmanblaidigmailcom

Received 26 February 2013 Accepted 28 April 2013

Academic Editor Dipakranjan Mal

Copyright copy 2013 Ottman Belaidi et alThis is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

The Fourier transform infrared spectra (FTIR) of 2-ethylhexyl acrylate have been measured in liquid phase The moleculargeometry vibrational frequencies and infrared intensities have been calculated by using density functional theory We foundtwo local minima representing s-cis and s-trans conformations for 2-ethylhexyl acrylate molecule The optimized geometriesat DFTB3LYP6-311+Glowastlowast are in good agreement with electron diffraction data of methyl acrylate for the acrylic group Thetwo conformers were used for the interpretation of the experimental infrared spectrum of title compound PED calculations arerepresented for a more complete and concise assignment There is one band in the infrared spectrum at 1646 cmminus1 that definitelyindicates the conformer with s-trans arrangement of acrylic moiety to be present or not in the liquid 2-ethylhexyl acrylate

1 Introduction

Alkyl acrylates are important monomers used in the manu-facture of polymers and copolymers Acrylates give polymersexhibiting outstanding transparency and aging proprietieswhich have made them of interest in a wide variety ofapplications [1ndash4] The structural data and the preferredmolecular conformation of these acrylates molecules wouldbe important for basic understanding of these polymers [5]

2-Ethylhexyl acrylate is used for production of paintadhesive and paper coating trade This monomer impartsflexibility and water resistance to the polymers [1 6] It is alsoused for curing polymeric materials [7ndash15]

To our best knowledge no structural data or detailedinterpretation of the vibrational spectra of 2-ethylhexyl acry-late is presented in the literature This prompted us to lookinto the vibrational spectroscopy of 2-ethylhexyl acrylatemore carefully

Many reports experimental [16ndash21] and theoretical [2022] show that acrylates and related compounds exhibitrotational isomerism with the planar s-trans and s-cis heavy-atom structures being the energetically most stable confor-mations However uncertainty continues to exist regarding

the relative stability of the two conformers Gas electrondiffraction studies onmethyl methacrylate [20] suggested thecistrans ratios to be equal to 2 1 On the other hand theIR spectrum of methyl methacrylate in Ar low temperaturematrix suggested an inverse ratio [23] Many experimentaland theoretical studies on methyl acrylate reported that thes-cis conformer is more stable than the s-trans conformer[24ndash29] However Bowles et al [30] assumed that the s-transconformer is more stable

2 Experimental

2-Ethylhexyl acrylate (purity greater than 99) was pur-chased from Sigma-Aldrich and it was used as it is withoutfurther purification The infrared spectra of liquid filmsplaced between the KBR windows were recorded within4000ndash700 cmminus1 rangewith a Perkin Elmer FTIR System-2000model

3 Computational

The optimizations of the stable conformers were conductedwith the density functional theory using 6-311+Glowastlowast basis

2 Organic Chemistry International

Figure 1 2-Ethylhexyl acrylate molecule s-cis and s-trans conformations

sets The DFT calculations were performed using Beckersquos 3-parameter (local nonlocal Hartree-Fock) hybrid exchangefunctionals with Lee-Yang-Parr correlational functionals(B3LYP) [31 32]

The harmonic vibrational frequencies of the stable con-formations were calculated at the same level of theoriesused for the calculated optimized geometries The calculatedfrequencies were scaled down by the wavenumber linearscaling procedure (WLS) of Yoshida et al [33 34] using thefollowing equation

]obs]calc= 10087 minus 00000163]calc (1)

All the calculations were carried out with the Gaussian03 program [35] The vibrational assignments of the normalmodes were provided on the basis of the calculated PEDs byusing the program GAR2PED [36]

4 Geometry Optimizations and Energies

The geometries optimizations were conducted at the B3LYP6-311+Glowastlowast assuming the s-cis and s-trans conformations Allthe optimized geometries are recognized as true minima dueto the lack of imaginary harmonic frequenciesThe results aregiven in Table 1 for s-cis and s-trans conformers respectivelyFor atoms numbering see Figure 1

In Table 1 the calculated bond lengths bond angles anddihedral angles have approximately the same values for thes-cis and s-trans conformers However some changes occurin going from the s-cis to the s-trans conformation Thebond angles C

1C4C6and C

4C6O8increase by 38∘ and 27∘

respectively while C4C6O7decreases by 25∘

The X ray structural data of s-cis methyl acrylate reportedby Egawa et al [21] and ab initio structure of s-trans methylacrylate reported by Tsuji et al [20] are very close to those wefound for 2-ethylhexyl acrylate molecule

The zero-point corrected energy of the s-cis conformationis 365102 times 106 calmol showing more stability than thecalculated one for the s-trans conformation The energy forthe latter conformation is 365101 times 106 calmol

5 Vibrational Analysis

The most stable conformers s-cis and s-trans 2-ethylhexylacrylate belong to the C

1point group Each conformer

represents 93 normal vibrational modes We juxtaposed theexperimental IR spectrum with the computed ones for bothconformers and we checked whether we can recognize themor not Tables 2 and 3 represent the calculated and scaledfundamental wavenumbers intensities of vibrational peaksand potential energy distribution along the internal coor-dinates obtained by DFTB3LYP6-311+Glowastlowast level of theoryThe corresponding experimental wavenumbers together withassignments are also reported in these tables The potentialenergy distributions are given as per the internal coordinatesystem recommended by Pulay et al using DFT [37]

51 The CH Stretching Vibrations Region (3200ndash2800 cmminus1Figure 2) In this region the calculations reveal the existenceof 20 vibrational normal modes for both the s-cis and s-trans conformers These normal modes are of approximatelythe same energies and intensities for both conformers Inthe IR spectrum in this region (Figure 2(a)) there are threegroups of bands two groups of strong bands and one groupof a very weak band In the latter there are three bands ofvery weak intensity at 3104 3069 and 3038 cmminus1 which arewell reproduced by the theoretical bands 3093 3047 and3012 cmminus1 respectively These bands are ascribed to the C

1H

and C4H stretching modes of vibrations of the vinyl group

The second group is composed of the strongest peaks at2961 and 2931 cmminus1 These two bands are well reproduced bythe theoretical bands 2963 and 2953 cmminus1 respectively Thethird group is composed of one peak slightly asymmetricat 2875 cmminus1 in the experimental IR spectrum this bandis reproduced at 2903 cmminus1 in the theoretical calculationsThe remaining bands below 2900 cmminus1 with higher intensityin these series of CH stretching vibrational modes may beassigned to reproduce the broad shoulder at 2861 cmminus1 Allthe theoretical peaks located between 3000 and 2860 cmminus1are ascribed to CH stretching of the methylene groups in

Organic Chemistry International 3

Table 1 Optimized geometries of s-cis and s-trans 2-ethylhexyl acrylate conformations by DFTB3LYP6-311+Glowastlowast

Internal coordinatesLevel of theoryDFT6-311+Glowastlowast

s-cis EHA

s-cis methylacrylatea

DFT6-311+Glowastlowasts-trans EHA

s-trans methylacrylateb

Bond lengths (A)C1H2 1084 1083 1074C1H3 1083 1084 1075C1C4 1331 1341(7) 1332 1319C4H5 1084 1084 1075C4C6 1486 1484(6) 1484 1484C6O7 1210 1211(2) 1211 1191C6O8 1351 1349(3) 1348 1325O8C9 1448 1439(3) 1448 1417C9H10 1093 1093C9H11 1093 1092C9C12 1526 1526C12H13 1098 1098C12C14 1543 1543C14H15 1097 1097C14H16 1096 1096C14C17 1531 1531C17C18 1094 1094C17H19 1093 1093C17H20 1092 1092C12C21 1549 1549C21H22 1097 1097C21H23 1094 1094C21C24 1534 1534C24H25 1097 1097C24H26 1095 1095C24C27 1533 1533C27H28 1097 1097C27H29 1097 1096C27C30 1531 1531C30H31 1094 1093C30H32 1094 1094C30H33 1094 1094

Bond angles (∘)H2C1H3 118049 117591H2C1C4 120479 121432 1217C1C4H5 122220 121739 1221C1C4C6 121072 1203(8) 124970 1242C4C6O7 125710 1261(5) 123066 1229C4C6O8 110564 1103(3) 113320 1137C6O8C9 116570 1164(5) 116493 1168O8C9H10 108658 108697O8C9H11 108313 108339O8C9C12 108522 108488

4 Organic Chemistry International

Table 1 Continued

Internal coordinatesLevel of theoryDFT6-311+Glowastlowast

s-cis EHA

s-cis methylacrylatea

DFT6-311+Glowastlowasts-trans EHA

s-trans methylacrylateb

C9 C12C14 108099 108115C12C14H15 108729 108720C12C14H16 108539 108544C12C14C17 115410 115400C14C17H18 111304 111345C14C17H19 110477 110478C14C17H20 112028 112001C9C12C21 111382 111384C12C21H22 109228 109231C12C21H23 109005 109019C12C21C24 114775 114824C21C24H25 108695 108731C21C24H26 110286 110291C21C24C27 113287 113308C24C27H28 109207 109229C24C27H29 109217 109208C24C27C30 113280 109208C27C30H31 111428 111428C27C30H32 111218 111209C27C30H33 111189 111202

Dihedral angles (∘)H3H2C1C4 180 minus179908H2C1C4H5 minus179977 179808H2C1C4C6 0037 0106C1C4C6O7 minus0166 178652C1C4C6O8 179844 minus1298C4C6O8C9 179896 179515C6O8C9H10 55606 55506C6O8C9H11 minus61282 minus61454C6O8C9C12 177303 177169O8C9 C12H13 55024 54463O8C9C12C14 171114 170547C9C12C14H15 61844 61568C9C12C14H16 minus53102 minus53378C9C12C14C17 minus175215 minus175516C12C14C17H18 56957 57249C12C14C17H19 176491 176782C12C14C17H20 minus63865 minus63596O8C9C12C21 minus63322 minus63915C9C12C21H22 minus96883 minus97147C9C12C21H23 18587 18279C9C12C21C24 139536 139298C12C21C24H25 minus59615 minus59061C12C21C24H26 56214 56717

Organic Chemistry International 5

Table 1 Continued

Internal coordinatesLevel of theoryDFT6-311+Glowastlowast

s-cis EHA

s-cis methylacrylatea

DFT6-311+Glowastlowasts-trans EHA

s-trans methylacrylateb

C12C21C24C27 178823 179360C21C24C27H28 minus58771 minus58768C21C24C27H29 56758 56753C21C24C27C30 179033 179029C24C27C30H31 179693 minus179983C24C27C30H32 minus60205 minus59888C24C27C30H33 59599 59917

aDetermined by a joint analysis of electron diffraction data and rotational constants [21]bDetermined by ab initio calculation at HF6ndash31Glowastlowast [20]

1

075

05

025

02800 2900 3000 3100 3200

Abso

rban

ce

Wavenumbers (cmminus1)

2861 28752931 2961

3038 3069 3104

(a)

100

80

60

40

20

0IR in

tens

ity (k

mm

ol)

2800 2900 3000 3100 3200Wavenumbers (cmminus1)

2884

2895

29113918

2936

2953

2963

3009 3048 3093

(b)

100

80

60

40

20

0IR in

tens

ity (k

mm

ol)

2800 2900 3000 3100 3200Wavenumbers (cmminus1)

28762880

2892

29102919

2934

2951

2963

3012 3048 3094

(c)

Figure 2 Comparison of the experimental IR (a) CH stretching region (3200ndash2800 cmminus1) with the appropriate theoretical DFTB3LYP6-311+Glowastlowast spectra ((b) and (c)) for s-cis and s-trans 2-ethylhexyl acrylate respectively

the butyl and the ethyl sides of the 2-ethylhexyl acrylatemolecule

52 The C=O and C=C Stretching and CH Bending Vibrations(1800ndash1200 cmminus1 Figure 3) In the IR spectrum (Figure 3(a))a very strong peak at 1727 cmminus1 represents the C=O stretching

band The simulated peaks are at 1735 and 1731 cmminus1 forthe s-cis and s-trans conformations these two frequenciescontribute to the experimental C=O stretching band

There are two C=C stretching bands in the experimentalspectra located at 1637 and 1619 cmminus1 of medium intensityThese bands are well reproduced by the theoretical bands at

6 Organic Chemistry International

Table 2 Frequencies and PEDs of s-cis 2-ethylhexyl acrylate

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

1 mdash 305017 307519 01860 120591 (O8C9) (63) 120591 (C9C12) (35)2 mdash 367273 3702484 19384 120591 (C9C12) (83) 120591 (O8C9) (17)3 mdash 482766 4865862 12435 120591 (C9C12) (98)

4 mdash 747391 7529828 00096 120588 (C30H3) (62) 120591 (C9C12) (17) 120591 (O8C9) (7) 120588 (C14H2)(7)

5 mdash 931493 9381827 07602 120591 (C9C12) (84) 120588 (C14H2) (15)6 mdash 996177 10032262 06102 120591 (C9C12) (76) 120591 (C9C12) (21)7 mdash 1159962 11678605 02949 120591 (C9C12) (94)8 mdash 1338201 13469244 07707 120591 (C9C12) (43) 120588 (C27H3) (31) 120588 (C9H2) (15)9 mdash 1461924 14711591 00469 120591 (C9C12) (58) 120588 (C9H2) (17) 120588 (C14H2) (16)10 mdash 2010708 20216112 18808 120591 (C9C12) (89) 120575 (C6O8C9) (5)11 mdash 2139423 21505753 27336 120591 (C9C12) (98)12 mdash 2341345 23527792 06986 120588 (C30H3) (94)13 mdash 2537618 25491989 12866 120588 (C30H3) (99)14 mdash 2654468 26660766 07334 120591 (C9C12) (83) 120588 (C30H3) (14)15 mdash 2851163 28627176 35548 120588 (C30H3) (78) 120591 (C9C12) (18)16 mdash 3157568 31687874 05814 120588 (C9H2) (89) 120588 (C17H3) (6)17 mdash 3551126 35614657 02263 120588 (C17H3) (36) 120588 (C9C12C14) (31) 120588 (C9H2) (19)

18 mdash 3759666 37693349 43994 120588 (C24C27C30) (27) 120588 (C9C12C14) (23) 120588 (C17H3) (17) 120575(C21C24C27) (10) 120588 (C9C12H13) (10) 120575 (C21H2) (8)

19 mdash 470318 47080422 06863 120588 (C9C12C21) (72) 120588 (C17H3) (11) 120588 (C9H2) (5)20 mdash 5120856 51226637 62054 120588 (C9C12C14) (80) 120588 (C9H2) (7) 120575 (C21C12C14) (6)21 mdash 5273488 52740376 01504 120588 (C9H2) (87) O (C6O7) (9)22 mdash 5339978 53399558 11100 120588 (C9C12C14) (77) 120588 (C6O8C9) (8)23 mdash 681189 67955184 31928 120588 (C9C12C14) (42) 120575 (O7C6C4) (42) 120588 (C6O8C9) (5)24 731 (m) 7312122 7288586 45137 120588 (C21C24C27) (99)25 748 (sh) 7795982 776474 10039 120588 (C27H2) (65) 120588 (C9C12C14) (18) 120588 (C14H2) (12)

26 770 (m) 7863101 78307298 16507 120588 (C27H2) (36) 120588 (C21H2) (32) 120588 (C14H2) (23) 120588(C17H3) (8)

27 811 (m) 8295925 82559191 249487 120588 (C9H2) (73) O (C6O7) (21) y (C1H2) (8)28 852 (w) 8523514 84792486 30736 120588 (C9C12C21) (82) 120588 (C9H2) (16)

29 896 (w) 9016472 89624016 10870 120588 (C9C12H21) (62) 120596 (C24H2) (16) y (C21H2) (9) 120575(C30H3) (8)

30 mdash 9068585 90134317 10553 120588 (C9C12H21) (86) 120588 (C9H2) (10)31 909 (w) 9172167 91148352 72928 120588 (C9H2) (58) 120596 (C27H2) (27) 120588 (O7C6O8) (12)32 933 (sh) 9478927 94149381 59570 120575 (C14C12H3) (50) 120596 (C27H2) (46)

33 962 (m) 9836705 97645643 251442 120588 (C9C12H13) (83) 120575 (C6O8C9) (21) y (C21H2) (14) y(C27H2) (11) y (C14H2) (11)

34 984 (m) 10069955 99922751 255334 120596 (C1H2) (84) y (C14H2) (10)

35 mdash 10169241 100891495 51103 120588 (C14H2) (41) 120588 (C9C12C21) (24) 120575 (C12C21C24) (23) 120588(C17H3) (7)

36 1015 (sh) 10232765 101511136 260306 o (C4H5) (99)37 mdash 10258451 101761651 19504 120575 (C9C12C14) (98) ] (C9O8) (5)38 1025 (sh) 10459956 103726182 278636 y (C24H2) (42) ] (C9C12) (42) ] (O8C9) (6)39 mdash 10621068 105295957 04109 120588 (C14C12H13) (83) ] (C27C30) (12)40 mdash 10659864 105673835 04863 ] (C14C17) (83) ] (C24C27) (11)41 mdash 10835238 107381387 16531 120596 (C9H2) (83) 120596 (C21H2) (15)42 1057 (m) 10894787 107960965 22238 120588 (C9H2) (84) 120596 (C27H2) (14)

Organic Chemistry International 7

Table 2 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

43 mdash 11505508 113898319 19252 120588 (C9C12H13) (96)

44 1116 (w) 11685589 115646723 118316 120575 (C12C21C24) (67) 120588 (C14C12H13) (9) 120588 (O8C9C12) (7)120575 (C14C12C21) (67)

45 1060 (sh) 11856606 117306145 00857 120575 (C9C12C14) (63) 120588 (C30H3) (26) 120575 (C12C14C17) (6)46 1191 12051044 11919167 6261232 120588 (C6C4H5) (87)47 mdash 12437853 12293901 03621 y (C21H2) (94) y (C27H2) (5)48 mdash 12586429 124377093 10505 120588 (C9H2) (76) 120596 (C21H2) (23)49 mdash 12817118 12660853 07178 y (C14H2) (55) 120596 (C21H2) (44)50 mdash 13003301 128408198 13337 120596 (C21H2) (93)

51 mdash 13179028 130105761 111581 120596 (C24H2) (24) 120588 (C9C12H13) (17) y (C14H2) (13) 120596(C27H2) (7) 120588 (C6O8C9) (5)

52 1272 13245992 130752384 683227 y (C27H2) (37) 120588 (C9C12H13) (29) y (C21H2) (22) y(C14H2) (6)

53 1295 13282386 131103753 60034 y (C27H2) (93)54 mdash 13381682 132062195 05711 y (C24H2) (70) y (C27H2) (28)55 1340 13610156 134266291 13124 120596 (C21H2) (78) 120596 (C9H2) (21)56 mdash 13812224 13621423 04732 120588 (C9C12C21) (78) 120596 (C21H2) (21)57 1357 13942309 137467547 33349 120596 (C9H2) (95)58 mdash 14045719 138463467 45032 120596 (C24H2) (95) 120596 (C21H2) (5)59 1381 14109338 139075996 73272 120596 (C21H2) (97)60 mdash 14141585 139386422 23703 120596 (C21H2) (99)61 mdash 14180649 139762426 04645 120596 (C21H2) (93) 120596 (C14H2) (6)62 1408 1437761 141657487 831633 120596 (C9H2) (49) 120596 (C21H2) (26) 120575 (CH2) (20)

63 mdash 14861635 146309161 10310 120575 (C21H2) (40) 120575 (C24H2) (20) 120575 (C12C21C24) (12) 120575(C14H2) (7)

64 mdash 14883957 1465235 10310 120575 (C27H2) (29) 120575 (C21H2) (28) 120575 (C24H2) (18) 120575(C12C21C24) (14) 120575 (C14H2) (10) 120575 (C27H2) (10)

65 mdash 1492293 146897685 13617 120575 (C21H2) (67) 120575 (C27H2) (11) 120575 (C14H2) (7)66 mdash 14999113 147628987 83925 120575 (C30H3) (88) 120575 (C27H2) (10)

67 mdash 15017672 147807111 43738 120575 (C21H2) (29) 120575 (C30H3) (28) 120575 (C24H2) (15) 120575(C21C12H13) (11) 120575 (C14H2) (6)

68 mdash 1503707 147993276 35078 120575 (C27H2) (31) 120575 (C21H2) (29) 120575 (C9H2) (18)

69 1464 15093473 148534511 99123 120575 (C17H3) (27) 120575 (C27H2) (26) 120575 (C21H2) (10) 120575(C12C21C24) (8) 120575 (C24H2) (7) 120575 (C12C14C21) (6)

70 mdash 15106836 148662726 108575 120575 (C21H2) (83) 120575 (C27H2) (10)

71 mdash 15154657 149121508 60184 120575 (C24H2) (42) 120575 (C21C24C27) (25) 120575 (C27H2) (13) 120575(C21H2) (10)

72 1637 16875503 165581242 269151 ] (C1C4) (87) 120575 (C1H2) (7)

73 1727 1770955 173524092 2434946 ] (C6O7) (80) 120575 (O8C9H12) (7) 120575 (C21H2) (5) ] (C4C6)(5)

74 mdash 29973914 287702371 27860 ] (C21H22) (45) ] (C14H2) (33) ] (C12H13) (14)75 mdash 29998142 287923075 17988 ] (C21H2) (76) ] (C24H2) (14)

76 mdash 30020159 288123622 138469 ] (C27H2) (33) ] (C24H2) (32) ] (C30H31) (22) ](C21H2) (6)

77 mdash 30058916 288476609 146381 ] (C21H2) (74) ] (C14H2) (14) ] (C12H13) (5)78 2861 30145745 289267245 457319 ] (C12H13) (63) ] (C30H31) (31)79 2875 30180275 289581595 559324 ] (C30H31) (98)80 mdash 30238407 290110723 222942 ] (C17H19) (58) ] (C17H18) (29)

81 mdash 30261436 290320306 164278 ] (C17H19) (32) ] (C14H2) (29) ] (C17H18) (15) ](C30C31) (8) ] (C21H2) (6)

82 mdash 30348324 291110906 351134 ] (C14H2) (96)

8 Organic Chemistry International

Table 2 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

83 mdash 30419158 291755246 160910 ] (C27H2) (38) ] (C9H2) (20) ] (C14H2) (19) ] (C21H2)(6) ] (C24H) (6)

84 mdash 30431697 29186929 145616 ] (C27H2) (47) ] (C9H2) (26) ] (C24H2) (10) ] (C14H2)(7)

85 mdash 3062906 293663657 465673 ] (C21H2) (55) ] (C27H2) (25) ] (C24H2) (9) ] (C12H13)(5)

86 2931 30788255 295110087 858987 ] (C27H2) (62) ] (C27H30) (10) ] 295503236 (C30H3)(9) ] (C9H2) (6) ] (C17H19) (6)

87 mdash 30831541 295503236 455349 ] (C30H31) (99)

88 mdash 30845244 295627682 351235 ] (C17H19) (67) ] (C17C19) (67) ] (C17C18) (17) ](C30H31) (15)

89 mdash 30879105 29593517 195239 ] (C9H2) (63) ] (O8C9) (16) ]-(C12H13) (11) ] (C17C19)(6)

90 2961 30931423 296410191 561433 ] (C17H19) (38) ] (C9H2) (26) ] (C17H20) (12) ](C14H2) (10) ] (C17H18) (9)

91 3038 31428663 300920422 51952 ] (C1C4) (45) ] (C1H2) (38) ] (C1H3) (9)92 mdash 3185092 304744188 32650 ] (C1H2) (95)93 3104 32359105 309338372 23617 ] (C4H5) (67) ] (C1H2) (22) ] (C1H3) (6)aAssignments and potential energy distribution (PED) (contributing ge 5) for vibrational normal mode Types of vibration ] stretching 120575 deformation oout-of-plane bending 120596 wagging y twisting 120588 rocking 120591 torsion w weak m medium sh shoulderbNormal mode number

1655 cmminus1 for s-cis conformer (Figure 3(b)) and 1647 cmminus1 forthe s-trans conformer (Figure 3(c)) The band at 1637 cmminus1may be used to definitely indicate that conformer with s-transarrangement of acrylic moiety is present or not in the liquid2-ethylhexyl acrylate

In the region from 1500 to 1200 cmminus1 in the experimen-tal spectrum (Figure 3) there are four bands of mediumintensity located at 1464 1408 1295 and 1272 cmminus1 Thebands of weak intensity of account of three are locatedat 1381 1357 and 1340 cmminus1 The calculated frequencies inthis region for the s-cis and s-trans conformations haveclose energies for each normal mode and the differencesdo not exceed 5 cmminus1 Based on the assignments reportedby Dulce et al [28] and our PED calculations we haveascribed the theoretical frequencies 1485 cmminus1 (s-cis) and1484 cmminus1 (s-trans) to the experimental band at 1464 cmminus1and they are representing a C

17H3symmetric bending The

calculated frequencies at 1479 1478 and 1476 cmminus1 may becontributed to the experimental band at 1464 cmminus1 due toits relatively large middle width of about 75 cmminus1 Mishra etal [38] have reported the experimental and the theoreticalIR spectra of 120574 form of oleic acid many peaks reported inthe region 1370 to 1220 cmminus1 for the CH

2carboxyl-sided

chain correspond approximately to those we found in ourspectrum from 1400 to 1200 cmminus1 and all of them may beassigned to CH

2deformation The assignment is based on

the bands intensities we found a good correlation betweenthe experimental and the theoretical spectra One shouldpoint out that the very intense bands predicted at 1267 and

1264 cmminus1 for s-trans form reproduce well the asymmetricshape of the experimental band at 1272 cmminus1 For bandsassignment see Tables 2 and 3

53 The CO Stretching and CH Bending Vibrations (1200ndash700 cmminus1 Figure 4) In this region in the IR spectrum thereis one very strong band at 1192 cmminus1 with weak shoulder at1160 cmminus1 and four medium intensity bands 1057 984 962shoulder at 933 and 811 cmminus1 The bands at 1116 1025 909896 852 770 and 727 cmminus1 (shoulder at 748 cmminus1) are ofweak intensity (Figure 4) Based on PEDs and intensities ofthe calculated frequencies we correlate the two intense bandsat 1192 and 1156 cmminus1 for the more stable and the less stableconformers to the band at 1191 cmminus1 in the experimentalIR spectrum The medium bands in IR spectrum are wellreproduced by the calculated peaks at 1079 999 976 941 and811 cmminus1 for the s-cis conformer and 1067 993 940 911 and828 cmminus1 for the s-trans conformer They may be ascribed toCH2rocking C

1H2wagging CCH rocking O

8C9 and C

1H2

twisting The peaks predicted by DFT at 728 and 783 cmminus1 ins-cis form and the peaks at 726 and 782 cmminus1 in the s-transformmay be correlated to the bands at 727 and 770 cmminus1 andthey are assigned to the CH

2deformations of the alkyl sides

of the title moleculeIn the IR spectra of 2-ethylhexyl acrylate reported in

this work there are a few bands with weak to very weakintensity which do not appear in the IR spectra of methylacrylate reported by Dulce et al [28] and George et al [39]These bands appear at 1157 1120 1052 and 1022 cmminus1 and they

Organic Chemistry International 9

Table 3 Frequencies and PEDs of s-trans 2-ethylhexyl acrylate

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

1 mdash 295569 2979981 13888 120591 (C21C24) (95)2 mdash 312922 3154848 12915 120591 (C21C24) (100)3 mdash 453002 4566086 00227 120591 (C21C24) (91) 120591 (O8C9) (6)4 mdash 69075 6959818 00113 120591 (C21C24) (98)5 mdash 916561 9231657 07304 120588 (C14H2) (64) 120591 (C9C12) (19) 120591 (C24C21) (15)6 mdash 106795 10753821 00788 120591 (C12C14) (92)7 mdash 116406 11719786 04606 120591 (O8C9) (90) 120591 (C21C24) (7)8 mdash 128002 12884855 07652 120591 (C21C24) (99)9 mdash 1377311 13862015 00737 120591 (C24C21) (94)10 mdash 1886176 18967867 24795 120591 (C24C21) (53) O (O8C9) (44)11 mdash 1964898 19756995 22280 120588 (C9H2) (82) 120591 (C9C12) (13)12 mdash 2346 23574391 17535 120588 (C30H3) (90) 120591 (C21C24) (7)13 mdash 2495865 25074252 32507 120588 (C30H3) (78) 120591 (C12C21) (19)14 mdash 2623636 26352416 12259 120588 (C9H2) (72) 120588 (C17H3) (22)15 mdash 2741636 27532362 05126 120591 (C12C21) (96)16 mdash 3352283 33631302 04554 120575 (C21C12C14) (93)17 mdash 3546136 355649 01655 120575 (C21C12C24) (95)18 mdash 406411 40725451 25402 120575 (C9C12C14) (92)19 mdash 4713032 47178287 10320 120588 (C9C12C14) (70) 120575 (C9C12C21) (12) 120588 (C14H2) (11)20 mdash 5098943 51009251 04733 y (C1H2) (86) O (C6O8) (12)

21 mdash 5140157 51418098 73067 120588 (C12C14C17) (38) 120588 (C9C12C21) (15) 120588 (C12C21) (14)120588 (C14C12H13) (13) 120588 (C1H2) (8) 120575 (C12C21C24) (7)

22 mdash 550859 55070531 22808 120588 (C9C12C14) (78) 120588 (C6O8C9) (9) 120588 (C1H2) (6)23 mdash 6360175 6349572 19146 120588 (O8C9C12) (97)24 727 (m) 7284338 72612214 43677 120588 (C9C12C21) (92)25 mdash 778027 77492902 06843 120588 (C9C12C21) (98)26 770 (m) 785397 78217532 18732 120588 (C21H2) (59) 120588 (C14H2) (36)27 811 (m) 8321364 82808904 215147 y (C1H2) (94) 120588 (C9H2) (5)

28 852 (w) 8501904 84580503 34731 120588 (C9C12C21) (47) 120588 (C9H2) (27) 120588 (C1H2) (15) ](C14C17) (5)

29 896 (w) 9017561 8963468 09206 120588 (C9C12C21) (73) 120588 (C21C24C27) (14)30 909 (w) 9065632 90105403 13451 120588 (C9C12C21) (46) 120588 (C9H2) (35) 120588 (C12C14C17) (9)31 933 (sh) 9170283 91129911 76343 120588 (O7C6O8) (86) 120588 (C9H2) (10)32 962 (m) 9470255 94064585 60649 120588 (C6O8C9) (99)33 mdash 9726775 96571834 70484 120588 (C6O8C9) (99)

34 984 (m) 10012212 99359199 344957 120596 (C1H2) (52) ] (C1C4) (15) 120575 (C4C6O8) (15) ] (C12C21)(15)

35 1015 (sh) 10171676 100915249 70006 ] (C12C21) (92)36 mdash 10219635 101383071 35045 ] (C21C24) (85) 120575 (C9C12O14) (9)37 1025 (sh) 10299052 102157589 185130 y (C1H2) (97)38 mdash 1040755 103215388 03554 ] (C21C24) (70) ] (C9C12) (14) y (C21H2) (5)39 mdash 10608287 105171458 55936 y (C21H2) (58) 120588 (C14C12H13) (29) 120588 (C14H2) (7)40 mdash 10640573 105485945 188097 ] (C21C24) (88) ] (C14C17) (8)41 1057 (m) 10767989 106726727 1926571 ] (C9O8) (82) ] (C14C17) (13)42 1060 (sh) 10895069 10796371 46500 120588 (C9H2) (40) 120575 (C9C12C21) (30) 120596 (C27H2) (25)43 1116 (w) 11506075 113903825 14631 120588 (C9C12H13) (51) 120575 (C9C12C21) (42)44 1191 11682621 115617915 32253 120588 (C14C12H13) (72) 120596 (C21H2) (16) 120588 (O8C9C12) (9)45 mdash 11850265 117244634 01695 120575 (C9C12C14) (94)

10 Organic Chemistry International

Table 3 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

46 mdash 1242923 122855525 17298 y (C21H2) (89)47 mdash 1258238 124337912 11546 120588 (C9C12C21) (35) 120596 (C21H2) (35) 120596 (C9H2) (27)48 mdash 12801017 126452842 779146 120596 (C21H2) (47) 120588 (C9C12C21) (37) 120588 (C9H2) (27)49 1272 1283202 126752616 3516365 120596 (C21H2) (60) y (C14H2) (27) y (C9H2) (10)50 mdash 12991286 128292094 44292 y (C9H2) (72) y (C21H2) (26)51 1295 13117811 129514505 72842 y (C14H2) (99)52 mdash 131875 130187577 68204 y (C14H2) (100)53 mdash 13264691 13093292 01479 y (C21H2) (97)54 mdash 13362199 131874163 04090 y (C24H2) (94) y (C21H2) (5)55 1340 1359997 134168063 10793 120596 (C21H2) (86) 120588 (C21C12C14) (7) 120596 (C9H2) (5)56 mdash 13800145 136097825 04801 120588 (C9C12C21) (43) 120575 (C9H12) (28) 120596 (C21H2) (25)

57 1357 13931134 137359902 28872 120596 (C9H2) (50) 120596 (C14H2) (23) 120575 (C21C12H13) (12) 120596(C21H2) (86)

58 mdash 14043849 138445461 09476 120596 (C21H2) (86) 120596 (C9H2) (12)59 mdash 14119509 139173911 08054 120596 (C9H2) (85) 120596 (C21H2) (14)60 1381 14145333 1394225 50233 120596 (C21H2) (54) 120596 (C9H2) (45)61 mdash 14173104 139689807 08100 120596 (C21H2) (89) 120596 (C9H2) (8)62 1408 14414398 142011302 305726 120596 (C9H2) (93) 120596 (C21H2) (5)

63 mdash 14831028 146015241 20326 120575 (C9H2) (38) 120575 (C21C12H13) (18) 120575 (C24C21C12) (15) 120575(C14H2) (13) 120575 (C24H2) (7) 120575 (C21H2) (6)

64 mdash 14876468 146451591 04300 120575 (C21C12H13) (33) 120575 (C27H2) (28) 120575 (C24H2) (20) 120575(C21H2) (10)

65 mdash 14916884 14683964 12432 120575 (C21H2) (54) 120575 (C9H2) (21) 120575 (C27H2) (11)

66 mdash 15000764 147644833 24692 120575 (C24H2) (32) 120575 (C21C12H13) (24) 120575 (C27H2) (8) 120575(C30H3) (8) 120575 (C21H2) (6)

67 mdash 1500718 147706413 70795 120575 (C30H3) (75) 120575 (C9H2) (11) 120575 (C27H2) (6)68 mdash 15025266 147879993 89950 120575 (C9H2) (74) 120575 (C17H3) (21)

69 1464 15081671 148421269 98400 120575 (C27H2) (26) 120575 (C30H3) (22) 120575 (C21H2) (14) 120575(C17H3) (14) 120575 (C24H2) (11)

70 mdash 15116225 148752807 105533 120575 (C21H2) (73) 120575 (C21C12H13) (6) 120575 (C24H2) (5) 120575(C17H3) (5)

71 mdash 1514069 14898752 56625 120575 (C24H2) (30) 120575 (C21H2) (29) 120575 (C21C24C27) (20) 120575(C27H2) (9)

72 1619 16787098 164738009 287096 ] (C1C4) (52) ] (C4C6) (22) 120575 (C9C12H13) (11) 120575(C21H2) (8)

73 1727 17668533 173134006 3155882 120575 (C9C12C21) (63) ] (C4C6) (16) 120575 (C21H2) (6) ](C6O7) (6)

74 mdash 2995932 287569419 20873 ] (C24H2) (35) ] (C14H2) (34) ] (C21H2) (25)

75 mdash 2998467 287800355 06759 ] (C24H2) (40) ] (C12H13) (29) ] (C21H2) (12) ](C14H2) (10)

76 mdash 3001649 288090203 135187 ] (C21H2) (92)77 mdash 30053152 288424116 132101 ] (C24H2) (87) ] (C24H2) (8)78 2861 3013385 289158948 585964 ] (C21H2) (45) ] (C30C32) (36) ] (C12H13) (12)79 2875 30178939 289569433 472871 ] (C30C32) (96)80 mdash 30236248 290091073 211397 ] (C14H12) (46) ] (C17H19) (32) ] (C17H18) (17)

81 mdash 30260401 290310887 159088 ] (C12H13) (30) ] (C17H19) (27) ] (C17H18) (13) ](C30C32) (12)

82 mdash 303455 291085214 329164 ] (C21H2) (66) ] (C14H2) (28)83 mdash 30404085 291618149 40314 ] (C21H2) (55) ] (C30H32) (27) ] (C12H13) (7)84 mdash 30437899 291925696 263738 ] (C21H2) (98)85 mdash 30609167 293482854 503404 ] (C21H2) (85) ] (C30C32) (12)86 2931 30786333 295092629 824131 ] (C30C32) (95)

Organic Chemistry International 11

Table 3 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

87 mdash 30833975 295525341 441245 ] (C30C32) (93)88 mdash 30842781 295605315 369537 ] (C17H19) (67) ] (C17H18) (18) ] (C21H2) (9)

89 mdash 30889498 296029541 151201 ] (C21H2) (52) ] (C9H2) (14) ] (C12H13) (14) ] (C14H2)(8) ] (C17H19) (7)

90 2961 30930704 296403663 595099 ] (C17H19) (36) ] (C14H2) (28) ] (C17H20) (10) ](C21H2) (10) ] (C17H18) (8) ] (C9H2) (6)

91 3038 31462567 301227655 52018 ] (C1C4) (50) ] (C1H2) (31) ] (C1H3) (10)92 3069 31857999 304808243 34136 ] (C4H5) (57) ] (C4C6) (23) ] (C1C4) (14)93 3104 3237707 309500628 44771 ] (C1H2) (70) ] (C1H3) (11) ] (C4H5) (7)aAssignments and potential energy distribution (PED) (contributing ge 5) for vibrational normal mode Types of vibration ] stretching 120575 deformation oout-of-plane bending 120596 wagging y twisting 120588 rocking 120591 torsion w weak m medium sh shoulderbNormal mode number

Abso

rban

ce

Wavenumbers (cmminus1)

121

08060402

01200 1300 1400 1500 1600 1700 1800

17721295

13401357

1381

14081464

1619 1637 1686

1727

(a)

IR in

tens

ity (k

mm

ol) 50

40

30

20

10

0

Wavenumbers (cmminus1)1200 1250 1300 1350 1400 1450 1500 1550 1600 1650 1700 1750 1800

1244 12841301

1311

1307

134113731390

1394

1417

14631476

14841491

1656

1735

(b)

IR in

tens

ity (k

mm

ol) 50

40

30

20

10

0

Wavenumbers (cmminus1)

1227

1264

12421284

1266

12941302

13411373 1393

1419

14601476

14871489

16461731

1200 1250 1300 1350 1400 1450 1500 1550 1600 1650 1700 1750 1800

(c)

Figure 3 Comparison of the experimental IR (a) C=O and C=C stretching and CH bending region (1800ndash1200 cmminus1) with the appropriatetheoretical B3LYP6-311+Glowastlowast spectra ((b) and (c)) for s-cis and s-trans 2-ethylhexyl acrylate respectively

are well correlated to the calculated peaks in DFT for bothconformers see Tables 2 and 3

The shoulders in the infrared spectrum at 1025 1015 cmminus1of weak to medium intensities may be correlated to the bands1037 1015 cmminus1 for s-cis and 1015 988 cmminus1 for the s-trans

conformer These bands are ascribed to the CH out-of-planebending modes of the vinyl group

The remaining bands of weak intensity in the experimen-tal IR spectrum are 909 896 and 852 cmminus1 These bandsare close to the ones at 911 996 and 847 cmminus1 for the s-cis

12 Organic Chemistry International

121

08060402

0700 800 900 1000 1100 1200

727 770

811

952 869909 933

962 9841015 1025

1057

11161060

1191

Abso

rban

ce

Wavenumbers (cmminus1)

(a)

20

10

0

728776 783

825

848895

900911 940 975

1000

10131037

1008 1152 11581180

1016

1139

1156

1191

700 800 900 1000 1100 1200Wavenumbers (cmminus1)

IR in

tens

ity (k

mm

ol)

(b)

725

775783

827

846 896

900

940 965

993

1009

10131021

1066

10331051

1054

1079 11381156

1171

700 800 900 1000 1100 1200Wavenumbers (cmminus1)

20

10

0IR in

tens

ity (k

mm

ol)

(c)

Figure 4 Comparison of the experimental IR (a) CO stretching and CH bending region (1200ndash700 cmminus1) with the appropriate theoreticalB3LYP6-311+Glowastlowast spectra ((b) and (c)) for s-cis and s-trans 2-ethylhexyl acrylate respectively

conformation of the titlemolecule All the vibrational normalmodes in this region are not pure and the majority of themwere ascribed according to PED calculations to CH bending(for more details see Tables 2 and 3)

54 Region below 700 cmminus1 This spectral region includesthe bands associated with C=CndashC CndashOndashC O=CndashO OndashCndashC CndashCndashC and CndashCndashC bending and torsion modes aboutthe single bonds OndashC and CndashC The frequencies and PEDcalculations are presented in Tables 2 and 3 Comparing the23 first normal modes for the two conformers we notice thatthey have the same type of vibrational modes However thenormal modes 16 17 and 18 represent CCC bending in the s-trans andCHandCCC rockingmodes in the s-cis conformer

Due to the lack of experimental data on this region wecompare our calculated frequencies to some experimental IRbands of related molecules presented in the literature Thebands at 356 254 116 and 100 cmminus1 are close to the bandsat 349(A1015840) 244(A10158401015840) 114(A10158401015840) and 114 cmminus1 (A10158401015840) reported byDulce et al [28] From the same work the bands at 530 244114 and 114 cmminus1 belonging to A10158401015840 symmetry for the s-trans

methyl acrylate in liquid state are close to our calculatedbands in DFT at 542 244 116 and 106 cmminus1

6 Conclusions

Themid-IR spectrum of 2-ethylhexyl acrylate was measuredand interpreted with support of the DFTB3LYP6-311+Glowastlowastcalculated vibrational spectra followed by potential energydistribution analysis Assuming the s-cis and s-trans confor-mations we found two stable conformations close in theirenergies The fully optimized geometries of s-cis and s-transconformations by DFTB3LYP6-311+Glowastlowast were comparedwith the experimental and theoretical data presented in theliterature on the methyl acrylate molecule The compari-son shows a good agreement The experimental vibrationalspectrum is in good agreement with the theoretical spectracalculated for the two conformations Two neighbor bandsin the IR spectrum at 1619 and 1637 cmminus1 may be used ascharacteristic bands to locate and distinguish the existence ofone or both conformations

Organic Chemistry International 13

References

[1] M Salkind E H Riddle and R W Keefer ldquoAcrylates andmethacrylates ester manufacture and marketsrdquo Industrial ampEngineering Chemistry Research vol 51 no 11 pp 1328ndash13341959

[2] K S Anseth S M Newman and C N Bowman ldquoPolymericdental composites properties and reaction behavior of multi-methacrylate dental restorationsrdquo Advances in Polymer Sciencevol 122 pp 176ndash217 1995

[3] J G Kloosterboer ldquoNetwork formation by chain crosslink-ing photopolymerization and its application in electronicsrdquoAdvances in Polymer Science vol 84 pp 1ndash61 1988

[4] K Matyjaszewski Y Gnanou and L Leibler MacromolecularEngineering vol 1 Wiley-VCH Weinheim Germany 2007

[5] M Orgill B L Baker and N L Owen ldquoFTIR studies ofconformational isomerism in acrylates and acrylic acidsrdquo Spec-trochimica Acta A vol 55 no 5 pp 1021ndash1024 1999

[6] M Salkind ldquoReaches into the marketrdquo Industrial amp EngineeringChemistry Research vol 56 pp 62ndash110 1964

[7] E Takacs K Dajka and L Wojnarovits ldquoStudy of high-energyradiation initiated polymerization of butyl acrylaterdquo RadiationPhysics and Chemistry vol 63 no 1 pp 41ndash44 2002

[8] H Yu J Peng M Zhai J Li G Wei and J Qiao ldquoRadiation-induced copolymerization of styrenen-butyl acrylate in thepresence of ultra-fine powdered styrene-butadiene rubberrdquoRadiation Physics and Chemistry vol 76 no 11-12 pp 1736ndash1740 2007

[9] P F Canamero J Luis de la Fuente and M Fermandez-GarcıaldquoCuring kinetic study using a well-controlled multifunctionalcopolymer based on glycidyl methacrylaterdquo European PolymerJournal vol 45 no 9 pp 2665ndash2673 2009

[10] DMathew C P ReghunadhanNair and K N Ninan ldquoPendantcyanate functional vinyl polymers and imidophenolic-triazinesthereof synthesis and thermal propertiesrdquo European PolymerJournal vol 36 no 6 pp 1195ndash1208 2000

[11] S Mitra S Chattopadhyay S Sabharwal and A K BhowmickldquoElectron beam crosslinked gels-Preparation characterizationand their effect on the mechanical dynamic mechanical andrheological properties of rubbersrdquoRadiation Physics and Chem-istry vol 79 no 2 pp 289ndash296 2010

[12] P Canamero-Martınez M Fermandez-Garcıa and J Luis de laFuente ldquoRheological cure characterization of a polyfunctionalepoxy acrylic resinrdquo Reactive and Functional Polymers vol 70no 10 pp 761ndash766 2010

[13] F Chu T McKenna and S Lu ldquoCuring kinetics of an acrylicresinepoxy resin system using dynamic scanning calorimetryrdquoEuropean Polymer Journal vol 33 no 6 pp 837ndash840 1997

[14] M C Douskey M S Gebhard A V McCormick et alldquoSpectroscopic studies of a novel cyclic oligomer with pendantalkoxysilane groupsrdquo Progress in Organic Coatings vol 45 no2-3 pp 145ndash157 2002

[15] R J Day P A Lovell and A A Wazzan ldquoToughened car-bonepoxy composites made by using coreshell particlesrdquoComposites Science andTechnology vol 61 no 1 pp 41ndash56 2001

[16] K Bolton D G Lister and J Sheridan ldquoRotational isomerismbarrier to internal rotation and electric dipole moment ofacrylic acid bymicrowave spectroscopyrdquo Journal of the ChemicalSociety Faraday Transactions 2 vol 70 pp 113ndash123 1974

[17] S W Charles F C Cullen N L Owen and G A WilliamsldquoInfrared spectrum and rotational isomerism of acrylic acidrdquoJournal of Molecular Structure vol 157 no 1ndash3 pp 17ndash25 1987

[18] K Bolton N L Owen and J Sheridan ldquoMicrowave spectra ofrotational isomers of acrylic acidrdquoNature vol 218 no 5138 pp266ndash267 1968

[19] G Williams N L Owen and J Sheridan ldquoSpectroscopicstudies of some substitutedmethyl formatesmdashpart 1microwavespectra and internal rotation barriers of methyl-fluoroformate-propiolate -cyanoformate -acrylate and -acetaterdquo Transac-tions of the Faraday Society vol 67 pp 922ndash949 1971

[20] T Tsuji H Ito H Takeuchi and S Konaka ldquoMolecularstructure and conformation ofmethylmethacrylate determinedby gas electron diffractionrdquo Journal of Molecular Structure vol475 no 1 pp 55ndash63 1999

[21] T Egawa S Maekawa H Fujiwara Takeuchi H Takeuchi andS Konaka ldquoMolecular structure and conformation of methylacrylate a gas electron diffraction study augmented by ab initiocalculation and rotational constantsrdquo Molecular Structure andSpectroscopy vol 352 pp 193ndash201 1995

[22] A Virdi V P Gupta and A Sharma ldquoAb initio studies onconformation vibrational and electronic spectra of methylmethacrylaterdquo Journal ofMolecular Structure vol 634 no 5 pp53ndash65 2003

[23] B L Baker M Orgill N L Owen et al ldquoThe molecularconformation of methyl methacrylatemdashan infrared and abinitio studyrdquo Journal of Molecular Structure vol 356 no 2 pp95ndash104 1995

[24] A N Mitra and I Santhanan ldquoRelativistic qqq spectra fromBethe-Salpeter premisesrdquo Physics Letters B vol 104 no 1 pp62ndash66 1981

[25] K Fan and J E Boggs ldquoRotational isomerism of acrylic acidrdquoJournal of Molecular Structure vol 157 no 1ndash3 pp 31ndash41 1987

[26] P Carmona and J Moreno ldquoThe infrared spectra and structureof methyl acrylaterdquo Journal of Molecular Structure vol 82 no3-4 pp 177ndash185 1982

[27] R J Loncharich T R Schwartz and K N Houk ldquoTheoreticalstudies of conformations of acrolein acrylic acid methyl acry-late and their Lewis acid complexesrdquo Journal of the AmericanChemical Society vol 109 no 1 pp 14ndash23 1987

[28] M Dulce G Faria J J C Teixeira-Dias and R FaustoldquoVibrational spectra and structure of methyl trans-crotonaterdquoVibrational Spectroscopy vol 2 no 2-3 pp 43ndash60 1991

[29] J J C Teixeira-Dias and R Fausto ldquoMolecular structure ofmethyl acrylate the high energy s-trans-(CO) conformerrdquoJournal of Molecular Structure vol 282 no 1-2 pp 123ndash1291993

[30] A J Bowles W O George and D B Cunliffe-Jones ldquoConfor-mations of some120572120573-unsaturated carbonyl compoundsmdashpart IIinfrared and Raman spectra of methyl and ethyl acrylates andtranscrotonatesrdquo Journal of the Chemical Society B pp 1070ndash1075 1970

[31] A D Becke ldquoDensity-functional thermochemistry IIIThe roleof exact exchangerdquoThe Journal of Chemical Physics vol 98 no7 pp 5648ndash5652 1993

[32] C Lee W Yang and R G Parr ldquoDevelopment of the Colle-Salvetti correlation-energy formula into a functional of theelectron densityrdquo Physical Review B vol 37 no 2 pp 785ndash7891988

[33] H Yoshida K Takeda J Okamura A Ehara and H MatsuuraldquoA new approach to vibrational analysis of large molecules bydensity functional theory wavenumber-linear scalingmethodrdquoJournal of Physical Chemistry A vol 106 no 14 pp 3580ndash35862002

14 Organic Chemistry International

[34] H Yoshida A Ehara and H Matsuura ldquoDensity functionalvibrational analysis using wavenumber-linear scale factorsrdquoChemical Physics Letters vol 325 no 4 pp 477ndash483 2000

[35] M J Frisch G W Trucks H B Schlegel et al Gaussian 03Revision B 01 Gaussian Pittsburgh Pa USA 2003

[36] J M L Martin and C Van Alsenoy GAR2PED A Program toObtain a Potential Energy Distribution from a Gaussian ArchiveRecord University of Antwerp 2009

[37] P Pulay G Fogarasi F Pang and J E Boggs ldquoSystematicab initio gradient calculation of molecular geometries forceconstants and dipole moment derivativesrdquo Journal of theAmerican Chemical Society vol 101 no 10 pp 2550ndash2560 1979

[38] S Mishra D Chaturvedi N Kumar P Tandon and H WSiesler ldquoAn ab initio and DFT study of structure and vibrationalspectra of 120574 form of Oleic acid comparison to experimentaldatardquo Chemistry and Physics of Lipids vol 163 no 2 pp 207ndash217 2010

[39] W O George D V Hassid and W F Maddams ldquoConfor-mations of some 120572120573-unsaturated carbonyl compoundsmdashpartIII infrared solution spectra of methyl [2H3]methyl ethyland [2H5]ethyl acrylates and trans-crotonatesrdquo Journal of theChemical Society Perkin Transactions 2 no 4 pp 400ndash4041972

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Page 2: Research Article Molecular Structure and Vibrational Spectra ...e molecular geometry, vibrational frequencies, and infrared intensities have been calculated by using density functional

2 Organic Chemistry International

Figure 1 2-Ethylhexyl acrylate molecule s-cis and s-trans conformations

sets The DFT calculations were performed using Beckersquos 3-parameter (local nonlocal Hartree-Fock) hybrid exchangefunctionals with Lee-Yang-Parr correlational functionals(B3LYP) [31 32]

The harmonic vibrational frequencies of the stable con-formations were calculated at the same level of theoriesused for the calculated optimized geometries The calculatedfrequencies were scaled down by the wavenumber linearscaling procedure (WLS) of Yoshida et al [33 34] using thefollowing equation

]obs]calc= 10087 minus 00000163]calc (1)

All the calculations were carried out with the Gaussian03 program [35] The vibrational assignments of the normalmodes were provided on the basis of the calculated PEDs byusing the program GAR2PED [36]

4 Geometry Optimizations and Energies

The geometries optimizations were conducted at the B3LYP6-311+Glowastlowast assuming the s-cis and s-trans conformations Allthe optimized geometries are recognized as true minima dueto the lack of imaginary harmonic frequenciesThe results aregiven in Table 1 for s-cis and s-trans conformers respectivelyFor atoms numbering see Figure 1

In Table 1 the calculated bond lengths bond angles anddihedral angles have approximately the same values for thes-cis and s-trans conformers However some changes occurin going from the s-cis to the s-trans conformation Thebond angles C

1C4C6and C

4C6O8increase by 38∘ and 27∘

respectively while C4C6O7decreases by 25∘

The X ray structural data of s-cis methyl acrylate reportedby Egawa et al [21] and ab initio structure of s-trans methylacrylate reported by Tsuji et al [20] are very close to those wefound for 2-ethylhexyl acrylate molecule

The zero-point corrected energy of the s-cis conformationis 365102 times 106 calmol showing more stability than thecalculated one for the s-trans conformation The energy forthe latter conformation is 365101 times 106 calmol

5 Vibrational Analysis

The most stable conformers s-cis and s-trans 2-ethylhexylacrylate belong to the C

1point group Each conformer

represents 93 normal vibrational modes We juxtaposed theexperimental IR spectrum with the computed ones for bothconformers and we checked whether we can recognize themor not Tables 2 and 3 represent the calculated and scaledfundamental wavenumbers intensities of vibrational peaksand potential energy distribution along the internal coor-dinates obtained by DFTB3LYP6-311+Glowastlowast level of theoryThe corresponding experimental wavenumbers together withassignments are also reported in these tables The potentialenergy distributions are given as per the internal coordinatesystem recommended by Pulay et al using DFT [37]

51 The CH Stretching Vibrations Region (3200ndash2800 cmminus1Figure 2) In this region the calculations reveal the existenceof 20 vibrational normal modes for both the s-cis and s-trans conformers These normal modes are of approximatelythe same energies and intensities for both conformers Inthe IR spectrum in this region (Figure 2(a)) there are threegroups of bands two groups of strong bands and one groupof a very weak band In the latter there are three bands ofvery weak intensity at 3104 3069 and 3038 cmminus1 which arewell reproduced by the theoretical bands 3093 3047 and3012 cmminus1 respectively These bands are ascribed to the C

1H

and C4H stretching modes of vibrations of the vinyl group

The second group is composed of the strongest peaks at2961 and 2931 cmminus1 These two bands are well reproduced bythe theoretical bands 2963 and 2953 cmminus1 respectively Thethird group is composed of one peak slightly asymmetricat 2875 cmminus1 in the experimental IR spectrum this bandis reproduced at 2903 cmminus1 in the theoretical calculationsThe remaining bands below 2900 cmminus1 with higher intensityin these series of CH stretching vibrational modes may beassigned to reproduce the broad shoulder at 2861 cmminus1 Allthe theoretical peaks located between 3000 and 2860 cmminus1are ascribed to CH stretching of the methylene groups in

Organic Chemistry International 3

Table 1 Optimized geometries of s-cis and s-trans 2-ethylhexyl acrylate conformations by DFTB3LYP6-311+Glowastlowast

Internal coordinatesLevel of theoryDFT6-311+Glowastlowast

s-cis EHA

s-cis methylacrylatea

DFT6-311+Glowastlowasts-trans EHA

s-trans methylacrylateb

Bond lengths (A)C1H2 1084 1083 1074C1H3 1083 1084 1075C1C4 1331 1341(7) 1332 1319C4H5 1084 1084 1075C4C6 1486 1484(6) 1484 1484C6O7 1210 1211(2) 1211 1191C6O8 1351 1349(3) 1348 1325O8C9 1448 1439(3) 1448 1417C9H10 1093 1093C9H11 1093 1092C9C12 1526 1526C12H13 1098 1098C12C14 1543 1543C14H15 1097 1097C14H16 1096 1096C14C17 1531 1531C17C18 1094 1094C17H19 1093 1093C17H20 1092 1092C12C21 1549 1549C21H22 1097 1097C21H23 1094 1094C21C24 1534 1534C24H25 1097 1097C24H26 1095 1095C24C27 1533 1533C27H28 1097 1097C27H29 1097 1096C27C30 1531 1531C30H31 1094 1093C30H32 1094 1094C30H33 1094 1094

Bond angles (∘)H2C1H3 118049 117591H2C1C4 120479 121432 1217C1C4H5 122220 121739 1221C1C4C6 121072 1203(8) 124970 1242C4C6O7 125710 1261(5) 123066 1229C4C6O8 110564 1103(3) 113320 1137C6O8C9 116570 1164(5) 116493 1168O8C9H10 108658 108697O8C9H11 108313 108339O8C9C12 108522 108488

4 Organic Chemistry International

Table 1 Continued

Internal coordinatesLevel of theoryDFT6-311+Glowastlowast

s-cis EHA

s-cis methylacrylatea

DFT6-311+Glowastlowasts-trans EHA

s-trans methylacrylateb

C9 C12C14 108099 108115C12C14H15 108729 108720C12C14H16 108539 108544C12C14C17 115410 115400C14C17H18 111304 111345C14C17H19 110477 110478C14C17H20 112028 112001C9C12C21 111382 111384C12C21H22 109228 109231C12C21H23 109005 109019C12C21C24 114775 114824C21C24H25 108695 108731C21C24H26 110286 110291C21C24C27 113287 113308C24C27H28 109207 109229C24C27H29 109217 109208C24C27C30 113280 109208C27C30H31 111428 111428C27C30H32 111218 111209C27C30H33 111189 111202

Dihedral angles (∘)H3H2C1C4 180 minus179908H2C1C4H5 minus179977 179808H2C1C4C6 0037 0106C1C4C6O7 minus0166 178652C1C4C6O8 179844 minus1298C4C6O8C9 179896 179515C6O8C9H10 55606 55506C6O8C9H11 minus61282 minus61454C6O8C9C12 177303 177169O8C9 C12H13 55024 54463O8C9C12C14 171114 170547C9C12C14H15 61844 61568C9C12C14H16 minus53102 minus53378C9C12C14C17 minus175215 minus175516C12C14C17H18 56957 57249C12C14C17H19 176491 176782C12C14C17H20 minus63865 minus63596O8C9C12C21 minus63322 minus63915C9C12C21H22 minus96883 minus97147C9C12C21H23 18587 18279C9C12C21C24 139536 139298C12C21C24H25 minus59615 minus59061C12C21C24H26 56214 56717

Organic Chemistry International 5

Table 1 Continued

Internal coordinatesLevel of theoryDFT6-311+Glowastlowast

s-cis EHA

s-cis methylacrylatea

DFT6-311+Glowastlowasts-trans EHA

s-trans methylacrylateb

C12C21C24C27 178823 179360C21C24C27H28 minus58771 minus58768C21C24C27H29 56758 56753C21C24C27C30 179033 179029C24C27C30H31 179693 minus179983C24C27C30H32 minus60205 minus59888C24C27C30H33 59599 59917

aDetermined by a joint analysis of electron diffraction data and rotational constants [21]bDetermined by ab initio calculation at HF6ndash31Glowastlowast [20]

1

075

05

025

02800 2900 3000 3100 3200

Abso

rban

ce

Wavenumbers (cmminus1)

2861 28752931 2961

3038 3069 3104

(a)

100

80

60

40

20

0IR in

tens

ity (k

mm

ol)

2800 2900 3000 3100 3200Wavenumbers (cmminus1)

2884

2895

29113918

2936

2953

2963

3009 3048 3093

(b)

100

80

60

40

20

0IR in

tens

ity (k

mm

ol)

2800 2900 3000 3100 3200Wavenumbers (cmminus1)

28762880

2892

29102919

2934

2951

2963

3012 3048 3094

(c)

Figure 2 Comparison of the experimental IR (a) CH stretching region (3200ndash2800 cmminus1) with the appropriate theoretical DFTB3LYP6-311+Glowastlowast spectra ((b) and (c)) for s-cis and s-trans 2-ethylhexyl acrylate respectively

the butyl and the ethyl sides of the 2-ethylhexyl acrylatemolecule

52 The C=O and C=C Stretching and CH Bending Vibrations(1800ndash1200 cmminus1 Figure 3) In the IR spectrum (Figure 3(a))a very strong peak at 1727 cmminus1 represents the C=O stretching

band The simulated peaks are at 1735 and 1731 cmminus1 forthe s-cis and s-trans conformations these two frequenciescontribute to the experimental C=O stretching band

There are two C=C stretching bands in the experimentalspectra located at 1637 and 1619 cmminus1 of medium intensityThese bands are well reproduced by the theoretical bands at

6 Organic Chemistry International

Table 2 Frequencies and PEDs of s-cis 2-ethylhexyl acrylate

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

1 mdash 305017 307519 01860 120591 (O8C9) (63) 120591 (C9C12) (35)2 mdash 367273 3702484 19384 120591 (C9C12) (83) 120591 (O8C9) (17)3 mdash 482766 4865862 12435 120591 (C9C12) (98)

4 mdash 747391 7529828 00096 120588 (C30H3) (62) 120591 (C9C12) (17) 120591 (O8C9) (7) 120588 (C14H2)(7)

5 mdash 931493 9381827 07602 120591 (C9C12) (84) 120588 (C14H2) (15)6 mdash 996177 10032262 06102 120591 (C9C12) (76) 120591 (C9C12) (21)7 mdash 1159962 11678605 02949 120591 (C9C12) (94)8 mdash 1338201 13469244 07707 120591 (C9C12) (43) 120588 (C27H3) (31) 120588 (C9H2) (15)9 mdash 1461924 14711591 00469 120591 (C9C12) (58) 120588 (C9H2) (17) 120588 (C14H2) (16)10 mdash 2010708 20216112 18808 120591 (C9C12) (89) 120575 (C6O8C9) (5)11 mdash 2139423 21505753 27336 120591 (C9C12) (98)12 mdash 2341345 23527792 06986 120588 (C30H3) (94)13 mdash 2537618 25491989 12866 120588 (C30H3) (99)14 mdash 2654468 26660766 07334 120591 (C9C12) (83) 120588 (C30H3) (14)15 mdash 2851163 28627176 35548 120588 (C30H3) (78) 120591 (C9C12) (18)16 mdash 3157568 31687874 05814 120588 (C9H2) (89) 120588 (C17H3) (6)17 mdash 3551126 35614657 02263 120588 (C17H3) (36) 120588 (C9C12C14) (31) 120588 (C9H2) (19)

18 mdash 3759666 37693349 43994 120588 (C24C27C30) (27) 120588 (C9C12C14) (23) 120588 (C17H3) (17) 120575(C21C24C27) (10) 120588 (C9C12H13) (10) 120575 (C21H2) (8)

19 mdash 470318 47080422 06863 120588 (C9C12C21) (72) 120588 (C17H3) (11) 120588 (C9H2) (5)20 mdash 5120856 51226637 62054 120588 (C9C12C14) (80) 120588 (C9H2) (7) 120575 (C21C12C14) (6)21 mdash 5273488 52740376 01504 120588 (C9H2) (87) O (C6O7) (9)22 mdash 5339978 53399558 11100 120588 (C9C12C14) (77) 120588 (C6O8C9) (8)23 mdash 681189 67955184 31928 120588 (C9C12C14) (42) 120575 (O7C6C4) (42) 120588 (C6O8C9) (5)24 731 (m) 7312122 7288586 45137 120588 (C21C24C27) (99)25 748 (sh) 7795982 776474 10039 120588 (C27H2) (65) 120588 (C9C12C14) (18) 120588 (C14H2) (12)

26 770 (m) 7863101 78307298 16507 120588 (C27H2) (36) 120588 (C21H2) (32) 120588 (C14H2) (23) 120588(C17H3) (8)

27 811 (m) 8295925 82559191 249487 120588 (C9H2) (73) O (C6O7) (21) y (C1H2) (8)28 852 (w) 8523514 84792486 30736 120588 (C9C12C21) (82) 120588 (C9H2) (16)

29 896 (w) 9016472 89624016 10870 120588 (C9C12H21) (62) 120596 (C24H2) (16) y (C21H2) (9) 120575(C30H3) (8)

30 mdash 9068585 90134317 10553 120588 (C9C12H21) (86) 120588 (C9H2) (10)31 909 (w) 9172167 91148352 72928 120588 (C9H2) (58) 120596 (C27H2) (27) 120588 (O7C6O8) (12)32 933 (sh) 9478927 94149381 59570 120575 (C14C12H3) (50) 120596 (C27H2) (46)

33 962 (m) 9836705 97645643 251442 120588 (C9C12H13) (83) 120575 (C6O8C9) (21) y (C21H2) (14) y(C27H2) (11) y (C14H2) (11)

34 984 (m) 10069955 99922751 255334 120596 (C1H2) (84) y (C14H2) (10)

35 mdash 10169241 100891495 51103 120588 (C14H2) (41) 120588 (C9C12C21) (24) 120575 (C12C21C24) (23) 120588(C17H3) (7)

36 1015 (sh) 10232765 101511136 260306 o (C4H5) (99)37 mdash 10258451 101761651 19504 120575 (C9C12C14) (98) ] (C9O8) (5)38 1025 (sh) 10459956 103726182 278636 y (C24H2) (42) ] (C9C12) (42) ] (O8C9) (6)39 mdash 10621068 105295957 04109 120588 (C14C12H13) (83) ] (C27C30) (12)40 mdash 10659864 105673835 04863 ] (C14C17) (83) ] (C24C27) (11)41 mdash 10835238 107381387 16531 120596 (C9H2) (83) 120596 (C21H2) (15)42 1057 (m) 10894787 107960965 22238 120588 (C9H2) (84) 120596 (C27H2) (14)

Organic Chemistry International 7

Table 2 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

43 mdash 11505508 113898319 19252 120588 (C9C12H13) (96)

44 1116 (w) 11685589 115646723 118316 120575 (C12C21C24) (67) 120588 (C14C12H13) (9) 120588 (O8C9C12) (7)120575 (C14C12C21) (67)

45 1060 (sh) 11856606 117306145 00857 120575 (C9C12C14) (63) 120588 (C30H3) (26) 120575 (C12C14C17) (6)46 1191 12051044 11919167 6261232 120588 (C6C4H5) (87)47 mdash 12437853 12293901 03621 y (C21H2) (94) y (C27H2) (5)48 mdash 12586429 124377093 10505 120588 (C9H2) (76) 120596 (C21H2) (23)49 mdash 12817118 12660853 07178 y (C14H2) (55) 120596 (C21H2) (44)50 mdash 13003301 128408198 13337 120596 (C21H2) (93)

51 mdash 13179028 130105761 111581 120596 (C24H2) (24) 120588 (C9C12H13) (17) y (C14H2) (13) 120596(C27H2) (7) 120588 (C6O8C9) (5)

52 1272 13245992 130752384 683227 y (C27H2) (37) 120588 (C9C12H13) (29) y (C21H2) (22) y(C14H2) (6)

53 1295 13282386 131103753 60034 y (C27H2) (93)54 mdash 13381682 132062195 05711 y (C24H2) (70) y (C27H2) (28)55 1340 13610156 134266291 13124 120596 (C21H2) (78) 120596 (C9H2) (21)56 mdash 13812224 13621423 04732 120588 (C9C12C21) (78) 120596 (C21H2) (21)57 1357 13942309 137467547 33349 120596 (C9H2) (95)58 mdash 14045719 138463467 45032 120596 (C24H2) (95) 120596 (C21H2) (5)59 1381 14109338 139075996 73272 120596 (C21H2) (97)60 mdash 14141585 139386422 23703 120596 (C21H2) (99)61 mdash 14180649 139762426 04645 120596 (C21H2) (93) 120596 (C14H2) (6)62 1408 1437761 141657487 831633 120596 (C9H2) (49) 120596 (C21H2) (26) 120575 (CH2) (20)

63 mdash 14861635 146309161 10310 120575 (C21H2) (40) 120575 (C24H2) (20) 120575 (C12C21C24) (12) 120575(C14H2) (7)

64 mdash 14883957 1465235 10310 120575 (C27H2) (29) 120575 (C21H2) (28) 120575 (C24H2) (18) 120575(C12C21C24) (14) 120575 (C14H2) (10) 120575 (C27H2) (10)

65 mdash 1492293 146897685 13617 120575 (C21H2) (67) 120575 (C27H2) (11) 120575 (C14H2) (7)66 mdash 14999113 147628987 83925 120575 (C30H3) (88) 120575 (C27H2) (10)

67 mdash 15017672 147807111 43738 120575 (C21H2) (29) 120575 (C30H3) (28) 120575 (C24H2) (15) 120575(C21C12H13) (11) 120575 (C14H2) (6)

68 mdash 1503707 147993276 35078 120575 (C27H2) (31) 120575 (C21H2) (29) 120575 (C9H2) (18)

69 1464 15093473 148534511 99123 120575 (C17H3) (27) 120575 (C27H2) (26) 120575 (C21H2) (10) 120575(C12C21C24) (8) 120575 (C24H2) (7) 120575 (C12C14C21) (6)

70 mdash 15106836 148662726 108575 120575 (C21H2) (83) 120575 (C27H2) (10)

71 mdash 15154657 149121508 60184 120575 (C24H2) (42) 120575 (C21C24C27) (25) 120575 (C27H2) (13) 120575(C21H2) (10)

72 1637 16875503 165581242 269151 ] (C1C4) (87) 120575 (C1H2) (7)

73 1727 1770955 173524092 2434946 ] (C6O7) (80) 120575 (O8C9H12) (7) 120575 (C21H2) (5) ] (C4C6)(5)

74 mdash 29973914 287702371 27860 ] (C21H22) (45) ] (C14H2) (33) ] (C12H13) (14)75 mdash 29998142 287923075 17988 ] (C21H2) (76) ] (C24H2) (14)

76 mdash 30020159 288123622 138469 ] (C27H2) (33) ] (C24H2) (32) ] (C30H31) (22) ](C21H2) (6)

77 mdash 30058916 288476609 146381 ] (C21H2) (74) ] (C14H2) (14) ] (C12H13) (5)78 2861 30145745 289267245 457319 ] (C12H13) (63) ] (C30H31) (31)79 2875 30180275 289581595 559324 ] (C30H31) (98)80 mdash 30238407 290110723 222942 ] (C17H19) (58) ] (C17H18) (29)

81 mdash 30261436 290320306 164278 ] (C17H19) (32) ] (C14H2) (29) ] (C17H18) (15) ](C30C31) (8) ] (C21H2) (6)

82 mdash 30348324 291110906 351134 ] (C14H2) (96)

8 Organic Chemistry International

Table 2 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

83 mdash 30419158 291755246 160910 ] (C27H2) (38) ] (C9H2) (20) ] (C14H2) (19) ] (C21H2)(6) ] (C24H) (6)

84 mdash 30431697 29186929 145616 ] (C27H2) (47) ] (C9H2) (26) ] (C24H2) (10) ] (C14H2)(7)

85 mdash 3062906 293663657 465673 ] (C21H2) (55) ] (C27H2) (25) ] (C24H2) (9) ] (C12H13)(5)

86 2931 30788255 295110087 858987 ] (C27H2) (62) ] (C27H30) (10) ] 295503236 (C30H3)(9) ] (C9H2) (6) ] (C17H19) (6)

87 mdash 30831541 295503236 455349 ] (C30H31) (99)

88 mdash 30845244 295627682 351235 ] (C17H19) (67) ] (C17C19) (67) ] (C17C18) (17) ](C30H31) (15)

89 mdash 30879105 29593517 195239 ] (C9H2) (63) ] (O8C9) (16) ]-(C12H13) (11) ] (C17C19)(6)

90 2961 30931423 296410191 561433 ] (C17H19) (38) ] (C9H2) (26) ] (C17H20) (12) ](C14H2) (10) ] (C17H18) (9)

91 3038 31428663 300920422 51952 ] (C1C4) (45) ] (C1H2) (38) ] (C1H3) (9)92 mdash 3185092 304744188 32650 ] (C1H2) (95)93 3104 32359105 309338372 23617 ] (C4H5) (67) ] (C1H2) (22) ] (C1H3) (6)aAssignments and potential energy distribution (PED) (contributing ge 5) for vibrational normal mode Types of vibration ] stretching 120575 deformation oout-of-plane bending 120596 wagging y twisting 120588 rocking 120591 torsion w weak m medium sh shoulderbNormal mode number

1655 cmminus1 for s-cis conformer (Figure 3(b)) and 1647 cmminus1 forthe s-trans conformer (Figure 3(c)) The band at 1637 cmminus1may be used to definitely indicate that conformer with s-transarrangement of acrylic moiety is present or not in the liquid2-ethylhexyl acrylate

In the region from 1500 to 1200 cmminus1 in the experimen-tal spectrum (Figure 3) there are four bands of mediumintensity located at 1464 1408 1295 and 1272 cmminus1 Thebands of weak intensity of account of three are locatedat 1381 1357 and 1340 cmminus1 The calculated frequencies inthis region for the s-cis and s-trans conformations haveclose energies for each normal mode and the differencesdo not exceed 5 cmminus1 Based on the assignments reportedby Dulce et al [28] and our PED calculations we haveascribed the theoretical frequencies 1485 cmminus1 (s-cis) and1484 cmminus1 (s-trans) to the experimental band at 1464 cmminus1and they are representing a C

17H3symmetric bending The

calculated frequencies at 1479 1478 and 1476 cmminus1 may becontributed to the experimental band at 1464 cmminus1 due toits relatively large middle width of about 75 cmminus1 Mishra etal [38] have reported the experimental and the theoreticalIR spectra of 120574 form of oleic acid many peaks reported inthe region 1370 to 1220 cmminus1 for the CH

2carboxyl-sided

chain correspond approximately to those we found in ourspectrum from 1400 to 1200 cmminus1 and all of them may beassigned to CH

2deformation The assignment is based on

the bands intensities we found a good correlation betweenthe experimental and the theoretical spectra One shouldpoint out that the very intense bands predicted at 1267 and

1264 cmminus1 for s-trans form reproduce well the asymmetricshape of the experimental band at 1272 cmminus1 For bandsassignment see Tables 2 and 3

53 The CO Stretching and CH Bending Vibrations (1200ndash700 cmminus1 Figure 4) In this region in the IR spectrum thereis one very strong band at 1192 cmminus1 with weak shoulder at1160 cmminus1 and four medium intensity bands 1057 984 962shoulder at 933 and 811 cmminus1 The bands at 1116 1025 909896 852 770 and 727 cmminus1 (shoulder at 748 cmminus1) are ofweak intensity (Figure 4) Based on PEDs and intensities ofthe calculated frequencies we correlate the two intense bandsat 1192 and 1156 cmminus1 for the more stable and the less stableconformers to the band at 1191 cmminus1 in the experimentalIR spectrum The medium bands in IR spectrum are wellreproduced by the calculated peaks at 1079 999 976 941 and811 cmminus1 for the s-cis conformer and 1067 993 940 911 and828 cmminus1 for the s-trans conformer They may be ascribed toCH2rocking C

1H2wagging CCH rocking O

8C9 and C

1H2

twisting The peaks predicted by DFT at 728 and 783 cmminus1 ins-cis form and the peaks at 726 and 782 cmminus1 in the s-transformmay be correlated to the bands at 727 and 770 cmminus1 andthey are assigned to the CH

2deformations of the alkyl sides

of the title moleculeIn the IR spectra of 2-ethylhexyl acrylate reported in

this work there are a few bands with weak to very weakintensity which do not appear in the IR spectra of methylacrylate reported by Dulce et al [28] and George et al [39]These bands appear at 1157 1120 1052 and 1022 cmminus1 and they

Organic Chemistry International 9

Table 3 Frequencies and PEDs of s-trans 2-ethylhexyl acrylate

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

1 mdash 295569 2979981 13888 120591 (C21C24) (95)2 mdash 312922 3154848 12915 120591 (C21C24) (100)3 mdash 453002 4566086 00227 120591 (C21C24) (91) 120591 (O8C9) (6)4 mdash 69075 6959818 00113 120591 (C21C24) (98)5 mdash 916561 9231657 07304 120588 (C14H2) (64) 120591 (C9C12) (19) 120591 (C24C21) (15)6 mdash 106795 10753821 00788 120591 (C12C14) (92)7 mdash 116406 11719786 04606 120591 (O8C9) (90) 120591 (C21C24) (7)8 mdash 128002 12884855 07652 120591 (C21C24) (99)9 mdash 1377311 13862015 00737 120591 (C24C21) (94)10 mdash 1886176 18967867 24795 120591 (C24C21) (53) O (O8C9) (44)11 mdash 1964898 19756995 22280 120588 (C9H2) (82) 120591 (C9C12) (13)12 mdash 2346 23574391 17535 120588 (C30H3) (90) 120591 (C21C24) (7)13 mdash 2495865 25074252 32507 120588 (C30H3) (78) 120591 (C12C21) (19)14 mdash 2623636 26352416 12259 120588 (C9H2) (72) 120588 (C17H3) (22)15 mdash 2741636 27532362 05126 120591 (C12C21) (96)16 mdash 3352283 33631302 04554 120575 (C21C12C14) (93)17 mdash 3546136 355649 01655 120575 (C21C12C24) (95)18 mdash 406411 40725451 25402 120575 (C9C12C14) (92)19 mdash 4713032 47178287 10320 120588 (C9C12C14) (70) 120575 (C9C12C21) (12) 120588 (C14H2) (11)20 mdash 5098943 51009251 04733 y (C1H2) (86) O (C6O8) (12)

21 mdash 5140157 51418098 73067 120588 (C12C14C17) (38) 120588 (C9C12C21) (15) 120588 (C12C21) (14)120588 (C14C12H13) (13) 120588 (C1H2) (8) 120575 (C12C21C24) (7)

22 mdash 550859 55070531 22808 120588 (C9C12C14) (78) 120588 (C6O8C9) (9) 120588 (C1H2) (6)23 mdash 6360175 6349572 19146 120588 (O8C9C12) (97)24 727 (m) 7284338 72612214 43677 120588 (C9C12C21) (92)25 mdash 778027 77492902 06843 120588 (C9C12C21) (98)26 770 (m) 785397 78217532 18732 120588 (C21H2) (59) 120588 (C14H2) (36)27 811 (m) 8321364 82808904 215147 y (C1H2) (94) 120588 (C9H2) (5)

28 852 (w) 8501904 84580503 34731 120588 (C9C12C21) (47) 120588 (C9H2) (27) 120588 (C1H2) (15) ](C14C17) (5)

29 896 (w) 9017561 8963468 09206 120588 (C9C12C21) (73) 120588 (C21C24C27) (14)30 909 (w) 9065632 90105403 13451 120588 (C9C12C21) (46) 120588 (C9H2) (35) 120588 (C12C14C17) (9)31 933 (sh) 9170283 91129911 76343 120588 (O7C6O8) (86) 120588 (C9H2) (10)32 962 (m) 9470255 94064585 60649 120588 (C6O8C9) (99)33 mdash 9726775 96571834 70484 120588 (C6O8C9) (99)

34 984 (m) 10012212 99359199 344957 120596 (C1H2) (52) ] (C1C4) (15) 120575 (C4C6O8) (15) ] (C12C21)(15)

35 1015 (sh) 10171676 100915249 70006 ] (C12C21) (92)36 mdash 10219635 101383071 35045 ] (C21C24) (85) 120575 (C9C12O14) (9)37 1025 (sh) 10299052 102157589 185130 y (C1H2) (97)38 mdash 1040755 103215388 03554 ] (C21C24) (70) ] (C9C12) (14) y (C21H2) (5)39 mdash 10608287 105171458 55936 y (C21H2) (58) 120588 (C14C12H13) (29) 120588 (C14H2) (7)40 mdash 10640573 105485945 188097 ] (C21C24) (88) ] (C14C17) (8)41 1057 (m) 10767989 106726727 1926571 ] (C9O8) (82) ] (C14C17) (13)42 1060 (sh) 10895069 10796371 46500 120588 (C9H2) (40) 120575 (C9C12C21) (30) 120596 (C27H2) (25)43 1116 (w) 11506075 113903825 14631 120588 (C9C12H13) (51) 120575 (C9C12C21) (42)44 1191 11682621 115617915 32253 120588 (C14C12H13) (72) 120596 (C21H2) (16) 120588 (O8C9C12) (9)45 mdash 11850265 117244634 01695 120575 (C9C12C14) (94)

10 Organic Chemistry International

Table 3 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

46 mdash 1242923 122855525 17298 y (C21H2) (89)47 mdash 1258238 124337912 11546 120588 (C9C12C21) (35) 120596 (C21H2) (35) 120596 (C9H2) (27)48 mdash 12801017 126452842 779146 120596 (C21H2) (47) 120588 (C9C12C21) (37) 120588 (C9H2) (27)49 1272 1283202 126752616 3516365 120596 (C21H2) (60) y (C14H2) (27) y (C9H2) (10)50 mdash 12991286 128292094 44292 y (C9H2) (72) y (C21H2) (26)51 1295 13117811 129514505 72842 y (C14H2) (99)52 mdash 131875 130187577 68204 y (C14H2) (100)53 mdash 13264691 13093292 01479 y (C21H2) (97)54 mdash 13362199 131874163 04090 y (C24H2) (94) y (C21H2) (5)55 1340 1359997 134168063 10793 120596 (C21H2) (86) 120588 (C21C12C14) (7) 120596 (C9H2) (5)56 mdash 13800145 136097825 04801 120588 (C9C12C21) (43) 120575 (C9H12) (28) 120596 (C21H2) (25)

57 1357 13931134 137359902 28872 120596 (C9H2) (50) 120596 (C14H2) (23) 120575 (C21C12H13) (12) 120596(C21H2) (86)

58 mdash 14043849 138445461 09476 120596 (C21H2) (86) 120596 (C9H2) (12)59 mdash 14119509 139173911 08054 120596 (C9H2) (85) 120596 (C21H2) (14)60 1381 14145333 1394225 50233 120596 (C21H2) (54) 120596 (C9H2) (45)61 mdash 14173104 139689807 08100 120596 (C21H2) (89) 120596 (C9H2) (8)62 1408 14414398 142011302 305726 120596 (C9H2) (93) 120596 (C21H2) (5)

63 mdash 14831028 146015241 20326 120575 (C9H2) (38) 120575 (C21C12H13) (18) 120575 (C24C21C12) (15) 120575(C14H2) (13) 120575 (C24H2) (7) 120575 (C21H2) (6)

64 mdash 14876468 146451591 04300 120575 (C21C12H13) (33) 120575 (C27H2) (28) 120575 (C24H2) (20) 120575(C21H2) (10)

65 mdash 14916884 14683964 12432 120575 (C21H2) (54) 120575 (C9H2) (21) 120575 (C27H2) (11)

66 mdash 15000764 147644833 24692 120575 (C24H2) (32) 120575 (C21C12H13) (24) 120575 (C27H2) (8) 120575(C30H3) (8) 120575 (C21H2) (6)

67 mdash 1500718 147706413 70795 120575 (C30H3) (75) 120575 (C9H2) (11) 120575 (C27H2) (6)68 mdash 15025266 147879993 89950 120575 (C9H2) (74) 120575 (C17H3) (21)

69 1464 15081671 148421269 98400 120575 (C27H2) (26) 120575 (C30H3) (22) 120575 (C21H2) (14) 120575(C17H3) (14) 120575 (C24H2) (11)

70 mdash 15116225 148752807 105533 120575 (C21H2) (73) 120575 (C21C12H13) (6) 120575 (C24H2) (5) 120575(C17H3) (5)

71 mdash 1514069 14898752 56625 120575 (C24H2) (30) 120575 (C21H2) (29) 120575 (C21C24C27) (20) 120575(C27H2) (9)

72 1619 16787098 164738009 287096 ] (C1C4) (52) ] (C4C6) (22) 120575 (C9C12H13) (11) 120575(C21H2) (8)

73 1727 17668533 173134006 3155882 120575 (C9C12C21) (63) ] (C4C6) (16) 120575 (C21H2) (6) ](C6O7) (6)

74 mdash 2995932 287569419 20873 ] (C24H2) (35) ] (C14H2) (34) ] (C21H2) (25)

75 mdash 2998467 287800355 06759 ] (C24H2) (40) ] (C12H13) (29) ] (C21H2) (12) ](C14H2) (10)

76 mdash 3001649 288090203 135187 ] (C21H2) (92)77 mdash 30053152 288424116 132101 ] (C24H2) (87) ] (C24H2) (8)78 2861 3013385 289158948 585964 ] (C21H2) (45) ] (C30C32) (36) ] (C12H13) (12)79 2875 30178939 289569433 472871 ] (C30C32) (96)80 mdash 30236248 290091073 211397 ] (C14H12) (46) ] (C17H19) (32) ] (C17H18) (17)

81 mdash 30260401 290310887 159088 ] (C12H13) (30) ] (C17H19) (27) ] (C17H18) (13) ](C30C32) (12)

82 mdash 303455 291085214 329164 ] (C21H2) (66) ] (C14H2) (28)83 mdash 30404085 291618149 40314 ] (C21H2) (55) ] (C30H32) (27) ] (C12H13) (7)84 mdash 30437899 291925696 263738 ] (C21H2) (98)85 mdash 30609167 293482854 503404 ] (C21H2) (85) ] (C30C32) (12)86 2931 30786333 295092629 824131 ] (C30C32) (95)

Organic Chemistry International 11

Table 3 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

87 mdash 30833975 295525341 441245 ] (C30C32) (93)88 mdash 30842781 295605315 369537 ] (C17H19) (67) ] (C17H18) (18) ] (C21H2) (9)

89 mdash 30889498 296029541 151201 ] (C21H2) (52) ] (C9H2) (14) ] (C12H13) (14) ] (C14H2)(8) ] (C17H19) (7)

90 2961 30930704 296403663 595099 ] (C17H19) (36) ] (C14H2) (28) ] (C17H20) (10) ](C21H2) (10) ] (C17H18) (8) ] (C9H2) (6)

91 3038 31462567 301227655 52018 ] (C1C4) (50) ] (C1H2) (31) ] (C1H3) (10)92 3069 31857999 304808243 34136 ] (C4H5) (57) ] (C4C6) (23) ] (C1C4) (14)93 3104 3237707 309500628 44771 ] (C1H2) (70) ] (C1H3) (11) ] (C4H5) (7)aAssignments and potential energy distribution (PED) (contributing ge 5) for vibrational normal mode Types of vibration ] stretching 120575 deformation oout-of-plane bending 120596 wagging y twisting 120588 rocking 120591 torsion w weak m medium sh shoulderbNormal mode number

Abso

rban

ce

Wavenumbers (cmminus1)

121

08060402

01200 1300 1400 1500 1600 1700 1800

17721295

13401357

1381

14081464

1619 1637 1686

1727

(a)

IR in

tens

ity (k

mm

ol) 50

40

30

20

10

0

Wavenumbers (cmminus1)1200 1250 1300 1350 1400 1450 1500 1550 1600 1650 1700 1750 1800

1244 12841301

1311

1307

134113731390

1394

1417

14631476

14841491

1656

1735

(b)

IR in

tens

ity (k

mm

ol) 50

40

30

20

10

0

Wavenumbers (cmminus1)

1227

1264

12421284

1266

12941302

13411373 1393

1419

14601476

14871489

16461731

1200 1250 1300 1350 1400 1450 1500 1550 1600 1650 1700 1750 1800

(c)

Figure 3 Comparison of the experimental IR (a) C=O and C=C stretching and CH bending region (1800ndash1200 cmminus1) with the appropriatetheoretical B3LYP6-311+Glowastlowast spectra ((b) and (c)) for s-cis and s-trans 2-ethylhexyl acrylate respectively

are well correlated to the calculated peaks in DFT for bothconformers see Tables 2 and 3

The shoulders in the infrared spectrum at 1025 1015 cmminus1of weak to medium intensities may be correlated to the bands1037 1015 cmminus1 for s-cis and 1015 988 cmminus1 for the s-trans

conformer These bands are ascribed to the CH out-of-planebending modes of the vinyl group

The remaining bands of weak intensity in the experimen-tal IR spectrum are 909 896 and 852 cmminus1 These bandsare close to the ones at 911 996 and 847 cmminus1 for the s-cis

12 Organic Chemistry International

121

08060402

0700 800 900 1000 1100 1200

727 770

811

952 869909 933

962 9841015 1025

1057

11161060

1191

Abso

rban

ce

Wavenumbers (cmminus1)

(a)

20

10

0

728776 783

825

848895

900911 940 975

1000

10131037

1008 1152 11581180

1016

1139

1156

1191

700 800 900 1000 1100 1200Wavenumbers (cmminus1)

IR in

tens

ity (k

mm

ol)

(b)

725

775783

827

846 896

900

940 965

993

1009

10131021

1066

10331051

1054

1079 11381156

1171

700 800 900 1000 1100 1200Wavenumbers (cmminus1)

20

10

0IR in

tens

ity (k

mm

ol)

(c)

Figure 4 Comparison of the experimental IR (a) CO stretching and CH bending region (1200ndash700 cmminus1) with the appropriate theoreticalB3LYP6-311+Glowastlowast spectra ((b) and (c)) for s-cis and s-trans 2-ethylhexyl acrylate respectively

conformation of the titlemolecule All the vibrational normalmodes in this region are not pure and the majority of themwere ascribed according to PED calculations to CH bending(for more details see Tables 2 and 3)

54 Region below 700 cmminus1 This spectral region includesthe bands associated with C=CndashC CndashOndashC O=CndashO OndashCndashC CndashCndashC and CndashCndashC bending and torsion modes aboutthe single bonds OndashC and CndashC The frequencies and PEDcalculations are presented in Tables 2 and 3 Comparing the23 first normal modes for the two conformers we notice thatthey have the same type of vibrational modes However thenormal modes 16 17 and 18 represent CCC bending in the s-trans andCHandCCC rockingmodes in the s-cis conformer

Due to the lack of experimental data on this region wecompare our calculated frequencies to some experimental IRbands of related molecules presented in the literature Thebands at 356 254 116 and 100 cmminus1 are close to the bandsat 349(A1015840) 244(A10158401015840) 114(A10158401015840) and 114 cmminus1 (A10158401015840) reported byDulce et al [28] From the same work the bands at 530 244114 and 114 cmminus1 belonging to A10158401015840 symmetry for the s-trans

methyl acrylate in liquid state are close to our calculatedbands in DFT at 542 244 116 and 106 cmminus1

6 Conclusions

Themid-IR spectrum of 2-ethylhexyl acrylate was measuredand interpreted with support of the DFTB3LYP6-311+Glowastlowastcalculated vibrational spectra followed by potential energydistribution analysis Assuming the s-cis and s-trans confor-mations we found two stable conformations close in theirenergies The fully optimized geometries of s-cis and s-transconformations by DFTB3LYP6-311+Glowastlowast were comparedwith the experimental and theoretical data presented in theliterature on the methyl acrylate molecule The compari-son shows a good agreement The experimental vibrationalspectrum is in good agreement with the theoretical spectracalculated for the two conformations Two neighbor bandsin the IR spectrum at 1619 and 1637 cmminus1 may be used ascharacteristic bands to locate and distinguish the existence ofone or both conformations

Organic Chemistry International 13

References

[1] M Salkind E H Riddle and R W Keefer ldquoAcrylates andmethacrylates ester manufacture and marketsrdquo Industrial ampEngineering Chemistry Research vol 51 no 11 pp 1328ndash13341959

[2] K S Anseth S M Newman and C N Bowman ldquoPolymericdental composites properties and reaction behavior of multi-methacrylate dental restorationsrdquo Advances in Polymer Sciencevol 122 pp 176ndash217 1995

[3] J G Kloosterboer ldquoNetwork formation by chain crosslink-ing photopolymerization and its application in electronicsrdquoAdvances in Polymer Science vol 84 pp 1ndash61 1988

[4] K Matyjaszewski Y Gnanou and L Leibler MacromolecularEngineering vol 1 Wiley-VCH Weinheim Germany 2007

[5] M Orgill B L Baker and N L Owen ldquoFTIR studies ofconformational isomerism in acrylates and acrylic acidsrdquo Spec-trochimica Acta A vol 55 no 5 pp 1021ndash1024 1999

[6] M Salkind ldquoReaches into the marketrdquo Industrial amp EngineeringChemistry Research vol 56 pp 62ndash110 1964

[7] E Takacs K Dajka and L Wojnarovits ldquoStudy of high-energyradiation initiated polymerization of butyl acrylaterdquo RadiationPhysics and Chemistry vol 63 no 1 pp 41ndash44 2002

[8] H Yu J Peng M Zhai J Li G Wei and J Qiao ldquoRadiation-induced copolymerization of styrenen-butyl acrylate in thepresence of ultra-fine powdered styrene-butadiene rubberrdquoRadiation Physics and Chemistry vol 76 no 11-12 pp 1736ndash1740 2007

[9] P F Canamero J Luis de la Fuente and M Fermandez-GarcıaldquoCuring kinetic study using a well-controlled multifunctionalcopolymer based on glycidyl methacrylaterdquo European PolymerJournal vol 45 no 9 pp 2665ndash2673 2009

[10] DMathew C P ReghunadhanNair and K N Ninan ldquoPendantcyanate functional vinyl polymers and imidophenolic-triazinesthereof synthesis and thermal propertiesrdquo European PolymerJournal vol 36 no 6 pp 1195ndash1208 2000

[11] S Mitra S Chattopadhyay S Sabharwal and A K BhowmickldquoElectron beam crosslinked gels-Preparation characterizationand their effect on the mechanical dynamic mechanical andrheological properties of rubbersrdquoRadiation Physics and Chem-istry vol 79 no 2 pp 289ndash296 2010

[12] P Canamero-Martınez M Fermandez-Garcıa and J Luis de laFuente ldquoRheological cure characterization of a polyfunctionalepoxy acrylic resinrdquo Reactive and Functional Polymers vol 70no 10 pp 761ndash766 2010

[13] F Chu T McKenna and S Lu ldquoCuring kinetics of an acrylicresinepoxy resin system using dynamic scanning calorimetryrdquoEuropean Polymer Journal vol 33 no 6 pp 837ndash840 1997

[14] M C Douskey M S Gebhard A V McCormick et alldquoSpectroscopic studies of a novel cyclic oligomer with pendantalkoxysilane groupsrdquo Progress in Organic Coatings vol 45 no2-3 pp 145ndash157 2002

[15] R J Day P A Lovell and A A Wazzan ldquoToughened car-bonepoxy composites made by using coreshell particlesrdquoComposites Science andTechnology vol 61 no 1 pp 41ndash56 2001

[16] K Bolton D G Lister and J Sheridan ldquoRotational isomerismbarrier to internal rotation and electric dipole moment ofacrylic acid bymicrowave spectroscopyrdquo Journal of the ChemicalSociety Faraday Transactions 2 vol 70 pp 113ndash123 1974

[17] S W Charles F C Cullen N L Owen and G A WilliamsldquoInfrared spectrum and rotational isomerism of acrylic acidrdquoJournal of Molecular Structure vol 157 no 1ndash3 pp 17ndash25 1987

[18] K Bolton N L Owen and J Sheridan ldquoMicrowave spectra ofrotational isomers of acrylic acidrdquoNature vol 218 no 5138 pp266ndash267 1968

[19] G Williams N L Owen and J Sheridan ldquoSpectroscopicstudies of some substitutedmethyl formatesmdashpart 1microwavespectra and internal rotation barriers of methyl-fluoroformate-propiolate -cyanoformate -acrylate and -acetaterdquo Transac-tions of the Faraday Society vol 67 pp 922ndash949 1971

[20] T Tsuji H Ito H Takeuchi and S Konaka ldquoMolecularstructure and conformation ofmethylmethacrylate determinedby gas electron diffractionrdquo Journal of Molecular Structure vol475 no 1 pp 55ndash63 1999

[21] T Egawa S Maekawa H Fujiwara Takeuchi H Takeuchi andS Konaka ldquoMolecular structure and conformation of methylacrylate a gas electron diffraction study augmented by ab initiocalculation and rotational constantsrdquo Molecular Structure andSpectroscopy vol 352 pp 193ndash201 1995

[22] A Virdi V P Gupta and A Sharma ldquoAb initio studies onconformation vibrational and electronic spectra of methylmethacrylaterdquo Journal ofMolecular Structure vol 634 no 5 pp53ndash65 2003

[23] B L Baker M Orgill N L Owen et al ldquoThe molecularconformation of methyl methacrylatemdashan infrared and abinitio studyrdquo Journal of Molecular Structure vol 356 no 2 pp95ndash104 1995

[24] A N Mitra and I Santhanan ldquoRelativistic qqq spectra fromBethe-Salpeter premisesrdquo Physics Letters B vol 104 no 1 pp62ndash66 1981

[25] K Fan and J E Boggs ldquoRotational isomerism of acrylic acidrdquoJournal of Molecular Structure vol 157 no 1ndash3 pp 31ndash41 1987

[26] P Carmona and J Moreno ldquoThe infrared spectra and structureof methyl acrylaterdquo Journal of Molecular Structure vol 82 no3-4 pp 177ndash185 1982

[27] R J Loncharich T R Schwartz and K N Houk ldquoTheoreticalstudies of conformations of acrolein acrylic acid methyl acry-late and their Lewis acid complexesrdquo Journal of the AmericanChemical Society vol 109 no 1 pp 14ndash23 1987

[28] M Dulce G Faria J J C Teixeira-Dias and R FaustoldquoVibrational spectra and structure of methyl trans-crotonaterdquoVibrational Spectroscopy vol 2 no 2-3 pp 43ndash60 1991

[29] J J C Teixeira-Dias and R Fausto ldquoMolecular structure ofmethyl acrylate the high energy s-trans-(CO) conformerrdquoJournal of Molecular Structure vol 282 no 1-2 pp 123ndash1291993

[30] A J Bowles W O George and D B Cunliffe-Jones ldquoConfor-mations of some120572120573-unsaturated carbonyl compoundsmdashpart IIinfrared and Raman spectra of methyl and ethyl acrylates andtranscrotonatesrdquo Journal of the Chemical Society B pp 1070ndash1075 1970

[31] A D Becke ldquoDensity-functional thermochemistry IIIThe roleof exact exchangerdquoThe Journal of Chemical Physics vol 98 no7 pp 5648ndash5652 1993

[32] C Lee W Yang and R G Parr ldquoDevelopment of the Colle-Salvetti correlation-energy formula into a functional of theelectron densityrdquo Physical Review B vol 37 no 2 pp 785ndash7891988

[33] H Yoshida K Takeda J Okamura A Ehara and H MatsuuraldquoA new approach to vibrational analysis of large molecules bydensity functional theory wavenumber-linear scalingmethodrdquoJournal of Physical Chemistry A vol 106 no 14 pp 3580ndash35862002

14 Organic Chemistry International

[34] H Yoshida A Ehara and H Matsuura ldquoDensity functionalvibrational analysis using wavenumber-linear scale factorsrdquoChemical Physics Letters vol 325 no 4 pp 477ndash483 2000

[35] M J Frisch G W Trucks H B Schlegel et al Gaussian 03Revision B 01 Gaussian Pittsburgh Pa USA 2003

[36] J M L Martin and C Van Alsenoy GAR2PED A Program toObtain a Potential Energy Distribution from a Gaussian ArchiveRecord University of Antwerp 2009

[37] P Pulay G Fogarasi F Pang and J E Boggs ldquoSystematicab initio gradient calculation of molecular geometries forceconstants and dipole moment derivativesrdquo Journal of theAmerican Chemical Society vol 101 no 10 pp 2550ndash2560 1979

[38] S Mishra D Chaturvedi N Kumar P Tandon and H WSiesler ldquoAn ab initio and DFT study of structure and vibrationalspectra of 120574 form of Oleic acid comparison to experimentaldatardquo Chemistry and Physics of Lipids vol 163 no 2 pp 207ndash217 2010

[39] W O George D V Hassid and W F Maddams ldquoConfor-mations of some 120572120573-unsaturated carbonyl compoundsmdashpartIII infrared solution spectra of methyl [2H3]methyl ethyland [2H5]ethyl acrylates and trans-crotonatesrdquo Journal of theChemical Society Perkin Transactions 2 no 4 pp 400ndash4041972

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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CatalystsJournal of

Page 3: Research Article Molecular Structure and Vibrational Spectra ...e molecular geometry, vibrational frequencies, and infrared intensities have been calculated by using density functional

Organic Chemistry International 3

Table 1 Optimized geometries of s-cis and s-trans 2-ethylhexyl acrylate conformations by DFTB3LYP6-311+Glowastlowast

Internal coordinatesLevel of theoryDFT6-311+Glowastlowast

s-cis EHA

s-cis methylacrylatea

DFT6-311+Glowastlowasts-trans EHA

s-trans methylacrylateb

Bond lengths (A)C1H2 1084 1083 1074C1H3 1083 1084 1075C1C4 1331 1341(7) 1332 1319C4H5 1084 1084 1075C4C6 1486 1484(6) 1484 1484C6O7 1210 1211(2) 1211 1191C6O8 1351 1349(3) 1348 1325O8C9 1448 1439(3) 1448 1417C9H10 1093 1093C9H11 1093 1092C9C12 1526 1526C12H13 1098 1098C12C14 1543 1543C14H15 1097 1097C14H16 1096 1096C14C17 1531 1531C17C18 1094 1094C17H19 1093 1093C17H20 1092 1092C12C21 1549 1549C21H22 1097 1097C21H23 1094 1094C21C24 1534 1534C24H25 1097 1097C24H26 1095 1095C24C27 1533 1533C27H28 1097 1097C27H29 1097 1096C27C30 1531 1531C30H31 1094 1093C30H32 1094 1094C30H33 1094 1094

Bond angles (∘)H2C1H3 118049 117591H2C1C4 120479 121432 1217C1C4H5 122220 121739 1221C1C4C6 121072 1203(8) 124970 1242C4C6O7 125710 1261(5) 123066 1229C4C6O8 110564 1103(3) 113320 1137C6O8C9 116570 1164(5) 116493 1168O8C9H10 108658 108697O8C9H11 108313 108339O8C9C12 108522 108488

4 Organic Chemistry International

Table 1 Continued

Internal coordinatesLevel of theoryDFT6-311+Glowastlowast

s-cis EHA

s-cis methylacrylatea

DFT6-311+Glowastlowasts-trans EHA

s-trans methylacrylateb

C9 C12C14 108099 108115C12C14H15 108729 108720C12C14H16 108539 108544C12C14C17 115410 115400C14C17H18 111304 111345C14C17H19 110477 110478C14C17H20 112028 112001C9C12C21 111382 111384C12C21H22 109228 109231C12C21H23 109005 109019C12C21C24 114775 114824C21C24H25 108695 108731C21C24H26 110286 110291C21C24C27 113287 113308C24C27H28 109207 109229C24C27H29 109217 109208C24C27C30 113280 109208C27C30H31 111428 111428C27C30H32 111218 111209C27C30H33 111189 111202

Dihedral angles (∘)H3H2C1C4 180 minus179908H2C1C4H5 minus179977 179808H2C1C4C6 0037 0106C1C4C6O7 minus0166 178652C1C4C6O8 179844 minus1298C4C6O8C9 179896 179515C6O8C9H10 55606 55506C6O8C9H11 minus61282 minus61454C6O8C9C12 177303 177169O8C9 C12H13 55024 54463O8C9C12C14 171114 170547C9C12C14H15 61844 61568C9C12C14H16 minus53102 minus53378C9C12C14C17 minus175215 minus175516C12C14C17H18 56957 57249C12C14C17H19 176491 176782C12C14C17H20 minus63865 minus63596O8C9C12C21 minus63322 minus63915C9C12C21H22 minus96883 minus97147C9C12C21H23 18587 18279C9C12C21C24 139536 139298C12C21C24H25 minus59615 minus59061C12C21C24H26 56214 56717

Organic Chemistry International 5

Table 1 Continued

Internal coordinatesLevel of theoryDFT6-311+Glowastlowast

s-cis EHA

s-cis methylacrylatea

DFT6-311+Glowastlowasts-trans EHA

s-trans methylacrylateb

C12C21C24C27 178823 179360C21C24C27H28 minus58771 minus58768C21C24C27H29 56758 56753C21C24C27C30 179033 179029C24C27C30H31 179693 minus179983C24C27C30H32 minus60205 minus59888C24C27C30H33 59599 59917

aDetermined by a joint analysis of electron diffraction data and rotational constants [21]bDetermined by ab initio calculation at HF6ndash31Glowastlowast [20]

1

075

05

025

02800 2900 3000 3100 3200

Abso

rban

ce

Wavenumbers (cmminus1)

2861 28752931 2961

3038 3069 3104

(a)

100

80

60

40

20

0IR in

tens

ity (k

mm

ol)

2800 2900 3000 3100 3200Wavenumbers (cmminus1)

2884

2895

29113918

2936

2953

2963

3009 3048 3093

(b)

100

80

60

40

20

0IR in

tens

ity (k

mm

ol)

2800 2900 3000 3100 3200Wavenumbers (cmminus1)

28762880

2892

29102919

2934

2951

2963

3012 3048 3094

(c)

Figure 2 Comparison of the experimental IR (a) CH stretching region (3200ndash2800 cmminus1) with the appropriate theoretical DFTB3LYP6-311+Glowastlowast spectra ((b) and (c)) for s-cis and s-trans 2-ethylhexyl acrylate respectively

the butyl and the ethyl sides of the 2-ethylhexyl acrylatemolecule

52 The C=O and C=C Stretching and CH Bending Vibrations(1800ndash1200 cmminus1 Figure 3) In the IR spectrum (Figure 3(a))a very strong peak at 1727 cmminus1 represents the C=O stretching

band The simulated peaks are at 1735 and 1731 cmminus1 forthe s-cis and s-trans conformations these two frequenciescontribute to the experimental C=O stretching band

There are two C=C stretching bands in the experimentalspectra located at 1637 and 1619 cmminus1 of medium intensityThese bands are well reproduced by the theoretical bands at

6 Organic Chemistry International

Table 2 Frequencies and PEDs of s-cis 2-ethylhexyl acrylate

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

1 mdash 305017 307519 01860 120591 (O8C9) (63) 120591 (C9C12) (35)2 mdash 367273 3702484 19384 120591 (C9C12) (83) 120591 (O8C9) (17)3 mdash 482766 4865862 12435 120591 (C9C12) (98)

4 mdash 747391 7529828 00096 120588 (C30H3) (62) 120591 (C9C12) (17) 120591 (O8C9) (7) 120588 (C14H2)(7)

5 mdash 931493 9381827 07602 120591 (C9C12) (84) 120588 (C14H2) (15)6 mdash 996177 10032262 06102 120591 (C9C12) (76) 120591 (C9C12) (21)7 mdash 1159962 11678605 02949 120591 (C9C12) (94)8 mdash 1338201 13469244 07707 120591 (C9C12) (43) 120588 (C27H3) (31) 120588 (C9H2) (15)9 mdash 1461924 14711591 00469 120591 (C9C12) (58) 120588 (C9H2) (17) 120588 (C14H2) (16)10 mdash 2010708 20216112 18808 120591 (C9C12) (89) 120575 (C6O8C9) (5)11 mdash 2139423 21505753 27336 120591 (C9C12) (98)12 mdash 2341345 23527792 06986 120588 (C30H3) (94)13 mdash 2537618 25491989 12866 120588 (C30H3) (99)14 mdash 2654468 26660766 07334 120591 (C9C12) (83) 120588 (C30H3) (14)15 mdash 2851163 28627176 35548 120588 (C30H3) (78) 120591 (C9C12) (18)16 mdash 3157568 31687874 05814 120588 (C9H2) (89) 120588 (C17H3) (6)17 mdash 3551126 35614657 02263 120588 (C17H3) (36) 120588 (C9C12C14) (31) 120588 (C9H2) (19)

18 mdash 3759666 37693349 43994 120588 (C24C27C30) (27) 120588 (C9C12C14) (23) 120588 (C17H3) (17) 120575(C21C24C27) (10) 120588 (C9C12H13) (10) 120575 (C21H2) (8)

19 mdash 470318 47080422 06863 120588 (C9C12C21) (72) 120588 (C17H3) (11) 120588 (C9H2) (5)20 mdash 5120856 51226637 62054 120588 (C9C12C14) (80) 120588 (C9H2) (7) 120575 (C21C12C14) (6)21 mdash 5273488 52740376 01504 120588 (C9H2) (87) O (C6O7) (9)22 mdash 5339978 53399558 11100 120588 (C9C12C14) (77) 120588 (C6O8C9) (8)23 mdash 681189 67955184 31928 120588 (C9C12C14) (42) 120575 (O7C6C4) (42) 120588 (C6O8C9) (5)24 731 (m) 7312122 7288586 45137 120588 (C21C24C27) (99)25 748 (sh) 7795982 776474 10039 120588 (C27H2) (65) 120588 (C9C12C14) (18) 120588 (C14H2) (12)

26 770 (m) 7863101 78307298 16507 120588 (C27H2) (36) 120588 (C21H2) (32) 120588 (C14H2) (23) 120588(C17H3) (8)

27 811 (m) 8295925 82559191 249487 120588 (C9H2) (73) O (C6O7) (21) y (C1H2) (8)28 852 (w) 8523514 84792486 30736 120588 (C9C12C21) (82) 120588 (C9H2) (16)

29 896 (w) 9016472 89624016 10870 120588 (C9C12H21) (62) 120596 (C24H2) (16) y (C21H2) (9) 120575(C30H3) (8)

30 mdash 9068585 90134317 10553 120588 (C9C12H21) (86) 120588 (C9H2) (10)31 909 (w) 9172167 91148352 72928 120588 (C9H2) (58) 120596 (C27H2) (27) 120588 (O7C6O8) (12)32 933 (sh) 9478927 94149381 59570 120575 (C14C12H3) (50) 120596 (C27H2) (46)

33 962 (m) 9836705 97645643 251442 120588 (C9C12H13) (83) 120575 (C6O8C9) (21) y (C21H2) (14) y(C27H2) (11) y (C14H2) (11)

34 984 (m) 10069955 99922751 255334 120596 (C1H2) (84) y (C14H2) (10)

35 mdash 10169241 100891495 51103 120588 (C14H2) (41) 120588 (C9C12C21) (24) 120575 (C12C21C24) (23) 120588(C17H3) (7)

36 1015 (sh) 10232765 101511136 260306 o (C4H5) (99)37 mdash 10258451 101761651 19504 120575 (C9C12C14) (98) ] (C9O8) (5)38 1025 (sh) 10459956 103726182 278636 y (C24H2) (42) ] (C9C12) (42) ] (O8C9) (6)39 mdash 10621068 105295957 04109 120588 (C14C12H13) (83) ] (C27C30) (12)40 mdash 10659864 105673835 04863 ] (C14C17) (83) ] (C24C27) (11)41 mdash 10835238 107381387 16531 120596 (C9H2) (83) 120596 (C21H2) (15)42 1057 (m) 10894787 107960965 22238 120588 (C9H2) (84) 120596 (C27H2) (14)

Organic Chemistry International 7

Table 2 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

43 mdash 11505508 113898319 19252 120588 (C9C12H13) (96)

44 1116 (w) 11685589 115646723 118316 120575 (C12C21C24) (67) 120588 (C14C12H13) (9) 120588 (O8C9C12) (7)120575 (C14C12C21) (67)

45 1060 (sh) 11856606 117306145 00857 120575 (C9C12C14) (63) 120588 (C30H3) (26) 120575 (C12C14C17) (6)46 1191 12051044 11919167 6261232 120588 (C6C4H5) (87)47 mdash 12437853 12293901 03621 y (C21H2) (94) y (C27H2) (5)48 mdash 12586429 124377093 10505 120588 (C9H2) (76) 120596 (C21H2) (23)49 mdash 12817118 12660853 07178 y (C14H2) (55) 120596 (C21H2) (44)50 mdash 13003301 128408198 13337 120596 (C21H2) (93)

51 mdash 13179028 130105761 111581 120596 (C24H2) (24) 120588 (C9C12H13) (17) y (C14H2) (13) 120596(C27H2) (7) 120588 (C6O8C9) (5)

52 1272 13245992 130752384 683227 y (C27H2) (37) 120588 (C9C12H13) (29) y (C21H2) (22) y(C14H2) (6)

53 1295 13282386 131103753 60034 y (C27H2) (93)54 mdash 13381682 132062195 05711 y (C24H2) (70) y (C27H2) (28)55 1340 13610156 134266291 13124 120596 (C21H2) (78) 120596 (C9H2) (21)56 mdash 13812224 13621423 04732 120588 (C9C12C21) (78) 120596 (C21H2) (21)57 1357 13942309 137467547 33349 120596 (C9H2) (95)58 mdash 14045719 138463467 45032 120596 (C24H2) (95) 120596 (C21H2) (5)59 1381 14109338 139075996 73272 120596 (C21H2) (97)60 mdash 14141585 139386422 23703 120596 (C21H2) (99)61 mdash 14180649 139762426 04645 120596 (C21H2) (93) 120596 (C14H2) (6)62 1408 1437761 141657487 831633 120596 (C9H2) (49) 120596 (C21H2) (26) 120575 (CH2) (20)

63 mdash 14861635 146309161 10310 120575 (C21H2) (40) 120575 (C24H2) (20) 120575 (C12C21C24) (12) 120575(C14H2) (7)

64 mdash 14883957 1465235 10310 120575 (C27H2) (29) 120575 (C21H2) (28) 120575 (C24H2) (18) 120575(C12C21C24) (14) 120575 (C14H2) (10) 120575 (C27H2) (10)

65 mdash 1492293 146897685 13617 120575 (C21H2) (67) 120575 (C27H2) (11) 120575 (C14H2) (7)66 mdash 14999113 147628987 83925 120575 (C30H3) (88) 120575 (C27H2) (10)

67 mdash 15017672 147807111 43738 120575 (C21H2) (29) 120575 (C30H3) (28) 120575 (C24H2) (15) 120575(C21C12H13) (11) 120575 (C14H2) (6)

68 mdash 1503707 147993276 35078 120575 (C27H2) (31) 120575 (C21H2) (29) 120575 (C9H2) (18)

69 1464 15093473 148534511 99123 120575 (C17H3) (27) 120575 (C27H2) (26) 120575 (C21H2) (10) 120575(C12C21C24) (8) 120575 (C24H2) (7) 120575 (C12C14C21) (6)

70 mdash 15106836 148662726 108575 120575 (C21H2) (83) 120575 (C27H2) (10)

71 mdash 15154657 149121508 60184 120575 (C24H2) (42) 120575 (C21C24C27) (25) 120575 (C27H2) (13) 120575(C21H2) (10)

72 1637 16875503 165581242 269151 ] (C1C4) (87) 120575 (C1H2) (7)

73 1727 1770955 173524092 2434946 ] (C6O7) (80) 120575 (O8C9H12) (7) 120575 (C21H2) (5) ] (C4C6)(5)

74 mdash 29973914 287702371 27860 ] (C21H22) (45) ] (C14H2) (33) ] (C12H13) (14)75 mdash 29998142 287923075 17988 ] (C21H2) (76) ] (C24H2) (14)

76 mdash 30020159 288123622 138469 ] (C27H2) (33) ] (C24H2) (32) ] (C30H31) (22) ](C21H2) (6)

77 mdash 30058916 288476609 146381 ] (C21H2) (74) ] (C14H2) (14) ] (C12H13) (5)78 2861 30145745 289267245 457319 ] (C12H13) (63) ] (C30H31) (31)79 2875 30180275 289581595 559324 ] (C30H31) (98)80 mdash 30238407 290110723 222942 ] (C17H19) (58) ] (C17H18) (29)

81 mdash 30261436 290320306 164278 ] (C17H19) (32) ] (C14H2) (29) ] (C17H18) (15) ](C30C31) (8) ] (C21H2) (6)

82 mdash 30348324 291110906 351134 ] (C14H2) (96)

8 Organic Chemistry International

Table 2 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

83 mdash 30419158 291755246 160910 ] (C27H2) (38) ] (C9H2) (20) ] (C14H2) (19) ] (C21H2)(6) ] (C24H) (6)

84 mdash 30431697 29186929 145616 ] (C27H2) (47) ] (C9H2) (26) ] (C24H2) (10) ] (C14H2)(7)

85 mdash 3062906 293663657 465673 ] (C21H2) (55) ] (C27H2) (25) ] (C24H2) (9) ] (C12H13)(5)

86 2931 30788255 295110087 858987 ] (C27H2) (62) ] (C27H30) (10) ] 295503236 (C30H3)(9) ] (C9H2) (6) ] (C17H19) (6)

87 mdash 30831541 295503236 455349 ] (C30H31) (99)

88 mdash 30845244 295627682 351235 ] (C17H19) (67) ] (C17C19) (67) ] (C17C18) (17) ](C30H31) (15)

89 mdash 30879105 29593517 195239 ] (C9H2) (63) ] (O8C9) (16) ]-(C12H13) (11) ] (C17C19)(6)

90 2961 30931423 296410191 561433 ] (C17H19) (38) ] (C9H2) (26) ] (C17H20) (12) ](C14H2) (10) ] (C17H18) (9)

91 3038 31428663 300920422 51952 ] (C1C4) (45) ] (C1H2) (38) ] (C1H3) (9)92 mdash 3185092 304744188 32650 ] (C1H2) (95)93 3104 32359105 309338372 23617 ] (C4H5) (67) ] (C1H2) (22) ] (C1H3) (6)aAssignments and potential energy distribution (PED) (contributing ge 5) for vibrational normal mode Types of vibration ] stretching 120575 deformation oout-of-plane bending 120596 wagging y twisting 120588 rocking 120591 torsion w weak m medium sh shoulderbNormal mode number

1655 cmminus1 for s-cis conformer (Figure 3(b)) and 1647 cmminus1 forthe s-trans conformer (Figure 3(c)) The band at 1637 cmminus1may be used to definitely indicate that conformer with s-transarrangement of acrylic moiety is present or not in the liquid2-ethylhexyl acrylate

In the region from 1500 to 1200 cmminus1 in the experimen-tal spectrum (Figure 3) there are four bands of mediumintensity located at 1464 1408 1295 and 1272 cmminus1 Thebands of weak intensity of account of three are locatedat 1381 1357 and 1340 cmminus1 The calculated frequencies inthis region for the s-cis and s-trans conformations haveclose energies for each normal mode and the differencesdo not exceed 5 cmminus1 Based on the assignments reportedby Dulce et al [28] and our PED calculations we haveascribed the theoretical frequencies 1485 cmminus1 (s-cis) and1484 cmminus1 (s-trans) to the experimental band at 1464 cmminus1and they are representing a C

17H3symmetric bending The

calculated frequencies at 1479 1478 and 1476 cmminus1 may becontributed to the experimental band at 1464 cmminus1 due toits relatively large middle width of about 75 cmminus1 Mishra etal [38] have reported the experimental and the theoreticalIR spectra of 120574 form of oleic acid many peaks reported inthe region 1370 to 1220 cmminus1 for the CH

2carboxyl-sided

chain correspond approximately to those we found in ourspectrum from 1400 to 1200 cmminus1 and all of them may beassigned to CH

2deformation The assignment is based on

the bands intensities we found a good correlation betweenthe experimental and the theoretical spectra One shouldpoint out that the very intense bands predicted at 1267 and

1264 cmminus1 for s-trans form reproduce well the asymmetricshape of the experimental band at 1272 cmminus1 For bandsassignment see Tables 2 and 3

53 The CO Stretching and CH Bending Vibrations (1200ndash700 cmminus1 Figure 4) In this region in the IR spectrum thereis one very strong band at 1192 cmminus1 with weak shoulder at1160 cmminus1 and four medium intensity bands 1057 984 962shoulder at 933 and 811 cmminus1 The bands at 1116 1025 909896 852 770 and 727 cmminus1 (shoulder at 748 cmminus1) are ofweak intensity (Figure 4) Based on PEDs and intensities ofthe calculated frequencies we correlate the two intense bandsat 1192 and 1156 cmminus1 for the more stable and the less stableconformers to the band at 1191 cmminus1 in the experimentalIR spectrum The medium bands in IR spectrum are wellreproduced by the calculated peaks at 1079 999 976 941 and811 cmminus1 for the s-cis conformer and 1067 993 940 911 and828 cmminus1 for the s-trans conformer They may be ascribed toCH2rocking C

1H2wagging CCH rocking O

8C9 and C

1H2

twisting The peaks predicted by DFT at 728 and 783 cmminus1 ins-cis form and the peaks at 726 and 782 cmminus1 in the s-transformmay be correlated to the bands at 727 and 770 cmminus1 andthey are assigned to the CH

2deformations of the alkyl sides

of the title moleculeIn the IR spectra of 2-ethylhexyl acrylate reported in

this work there are a few bands with weak to very weakintensity which do not appear in the IR spectra of methylacrylate reported by Dulce et al [28] and George et al [39]These bands appear at 1157 1120 1052 and 1022 cmminus1 and they

Organic Chemistry International 9

Table 3 Frequencies and PEDs of s-trans 2-ethylhexyl acrylate

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

1 mdash 295569 2979981 13888 120591 (C21C24) (95)2 mdash 312922 3154848 12915 120591 (C21C24) (100)3 mdash 453002 4566086 00227 120591 (C21C24) (91) 120591 (O8C9) (6)4 mdash 69075 6959818 00113 120591 (C21C24) (98)5 mdash 916561 9231657 07304 120588 (C14H2) (64) 120591 (C9C12) (19) 120591 (C24C21) (15)6 mdash 106795 10753821 00788 120591 (C12C14) (92)7 mdash 116406 11719786 04606 120591 (O8C9) (90) 120591 (C21C24) (7)8 mdash 128002 12884855 07652 120591 (C21C24) (99)9 mdash 1377311 13862015 00737 120591 (C24C21) (94)10 mdash 1886176 18967867 24795 120591 (C24C21) (53) O (O8C9) (44)11 mdash 1964898 19756995 22280 120588 (C9H2) (82) 120591 (C9C12) (13)12 mdash 2346 23574391 17535 120588 (C30H3) (90) 120591 (C21C24) (7)13 mdash 2495865 25074252 32507 120588 (C30H3) (78) 120591 (C12C21) (19)14 mdash 2623636 26352416 12259 120588 (C9H2) (72) 120588 (C17H3) (22)15 mdash 2741636 27532362 05126 120591 (C12C21) (96)16 mdash 3352283 33631302 04554 120575 (C21C12C14) (93)17 mdash 3546136 355649 01655 120575 (C21C12C24) (95)18 mdash 406411 40725451 25402 120575 (C9C12C14) (92)19 mdash 4713032 47178287 10320 120588 (C9C12C14) (70) 120575 (C9C12C21) (12) 120588 (C14H2) (11)20 mdash 5098943 51009251 04733 y (C1H2) (86) O (C6O8) (12)

21 mdash 5140157 51418098 73067 120588 (C12C14C17) (38) 120588 (C9C12C21) (15) 120588 (C12C21) (14)120588 (C14C12H13) (13) 120588 (C1H2) (8) 120575 (C12C21C24) (7)

22 mdash 550859 55070531 22808 120588 (C9C12C14) (78) 120588 (C6O8C9) (9) 120588 (C1H2) (6)23 mdash 6360175 6349572 19146 120588 (O8C9C12) (97)24 727 (m) 7284338 72612214 43677 120588 (C9C12C21) (92)25 mdash 778027 77492902 06843 120588 (C9C12C21) (98)26 770 (m) 785397 78217532 18732 120588 (C21H2) (59) 120588 (C14H2) (36)27 811 (m) 8321364 82808904 215147 y (C1H2) (94) 120588 (C9H2) (5)

28 852 (w) 8501904 84580503 34731 120588 (C9C12C21) (47) 120588 (C9H2) (27) 120588 (C1H2) (15) ](C14C17) (5)

29 896 (w) 9017561 8963468 09206 120588 (C9C12C21) (73) 120588 (C21C24C27) (14)30 909 (w) 9065632 90105403 13451 120588 (C9C12C21) (46) 120588 (C9H2) (35) 120588 (C12C14C17) (9)31 933 (sh) 9170283 91129911 76343 120588 (O7C6O8) (86) 120588 (C9H2) (10)32 962 (m) 9470255 94064585 60649 120588 (C6O8C9) (99)33 mdash 9726775 96571834 70484 120588 (C6O8C9) (99)

34 984 (m) 10012212 99359199 344957 120596 (C1H2) (52) ] (C1C4) (15) 120575 (C4C6O8) (15) ] (C12C21)(15)

35 1015 (sh) 10171676 100915249 70006 ] (C12C21) (92)36 mdash 10219635 101383071 35045 ] (C21C24) (85) 120575 (C9C12O14) (9)37 1025 (sh) 10299052 102157589 185130 y (C1H2) (97)38 mdash 1040755 103215388 03554 ] (C21C24) (70) ] (C9C12) (14) y (C21H2) (5)39 mdash 10608287 105171458 55936 y (C21H2) (58) 120588 (C14C12H13) (29) 120588 (C14H2) (7)40 mdash 10640573 105485945 188097 ] (C21C24) (88) ] (C14C17) (8)41 1057 (m) 10767989 106726727 1926571 ] (C9O8) (82) ] (C14C17) (13)42 1060 (sh) 10895069 10796371 46500 120588 (C9H2) (40) 120575 (C9C12C21) (30) 120596 (C27H2) (25)43 1116 (w) 11506075 113903825 14631 120588 (C9C12H13) (51) 120575 (C9C12C21) (42)44 1191 11682621 115617915 32253 120588 (C14C12H13) (72) 120596 (C21H2) (16) 120588 (O8C9C12) (9)45 mdash 11850265 117244634 01695 120575 (C9C12C14) (94)

10 Organic Chemistry International

Table 3 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

46 mdash 1242923 122855525 17298 y (C21H2) (89)47 mdash 1258238 124337912 11546 120588 (C9C12C21) (35) 120596 (C21H2) (35) 120596 (C9H2) (27)48 mdash 12801017 126452842 779146 120596 (C21H2) (47) 120588 (C9C12C21) (37) 120588 (C9H2) (27)49 1272 1283202 126752616 3516365 120596 (C21H2) (60) y (C14H2) (27) y (C9H2) (10)50 mdash 12991286 128292094 44292 y (C9H2) (72) y (C21H2) (26)51 1295 13117811 129514505 72842 y (C14H2) (99)52 mdash 131875 130187577 68204 y (C14H2) (100)53 mdash 13264691 13093292 01479 y (C21H2) (97)54 mdash 13362199 131874163 04090 y (C24H2) (94) y (C21H2) (5)55 1340 1359997 134168063 10793 120596 (C21H2) (86) 120588 (C21C12C14) (7) 120596 (C9H2) (5)56 mdash 13800145 136097825 04801 120588 (C9C12C21) (43) 120575 (C9H12) (28) 120596 (C21H2) (25)

57 1357 13931134 137359902 28872 120596 (C9H2) (50) 120596 (C14H2) (23) 120575 (C21C12H13) (12) 120596(C21H2) (86)

58 mdash 14043849 138445461 09476 120596 (C21H2) (86) 120596 (C9H2) (12)59 mdash 14119509 139173911 08054 120596 (C9H2) (85) 120596 (C21H2) (14)60 1381 14145333 1394225 50233 120596 (C21H2) (54) 120596 (C9H2) (45)61 mdash 14173104 139689807 08100 120596 (C21H2) (89) 120596 (C9H2) (8)62 1408 14414398 142011302 305726 120596 (C9H2) (93) 120596 (C21H2) (5)

63 mdash 14831028 146015241 20326 120575 (C9H2) (38) 120575 (C21C12H13) (18) 120575 (C24C21C12) (15) 120575(C14H2) (13) 120575 (C24H2) (7) 120575 (C21H2) (6)

64 mdash 14876468 146451591 04300 120575 (C21C12H13) (33) 120575 (C27H2) (28) 120575 (C24H2) (20) 120575(C21H2) (10)

65 mdash 14916884 14683964 12432 120575 (C21H2) (54) 120575 (C9H2) (21) 120575 (C27H2) (11)

66 mdash 15000764 147644833 24692 120575 (C24H2) (32) 120575 (C21C12H13) (24) 120575 (C27H2) (8) 120575(C30H3) (8) 120575 (C21H2) (6)

67 mdash 1500718 147706413 70795 120575 (C30H3) (75) 120575 (C9H2) (11) 120575 (C27H2) (6)68 mdash 15025266 147879993 89950 120575 (C9H2) (74) 120575 (C17H3) (21)

69 1464 15081671 148421269 98400 120575 (C27H2) (26) 120575 (C30H3) (22) 120575 (C21H2) (14) 120575(C17H3) (14) 120575 (C24H2) (11)

70 mdash 15116225 148752807 105533 120575 (C21H2) (73) 120575 (C21C12H13) (6) 120575 (C24H2) (5) 120575(C17H3) (5)

71 mdash 1514069 14898752 56625 120575 (C24H2) (30) 120575 (C21H2) (29) 120575 (C21C24C27) (20) 120575(C27H2) (9)

72 1619 16787098 164738009 287096 ] (C1C4) (52) ] (C4C6) (22) 120575 (C9C12H13) (11) 120575(C21H2) (8)

73 1727 17668533 173134006 3155882 120575 (C9C12C21) (63) ] (C4C6) (16) 120575 (C21H2) (6) ](C6O7) (6)

74 mdash 2995932 287569419 20873 ] (C24H2) (35) ] (C14H2) (34) ] (C21H2) (25)

75 mdash 2998467 287800355 06759 ] (C24H2) (40) ] (C12H13) (29) ] (C21H2) (12) ](C14H2) (10)

76 mdash 3001649 288090203 135187 ] (C21H2) (92)77 mdash 30053152 288424116 132101 ] (C24H2) (87) ] (C24H2) (8)78 2861 3013385 289158948 585964 ] (C21H2) (45) ] (C30C32) (36) ] (C12H13) (12)79 2875 30178939 289569433 472871 ] (C30C32) (96)80 mdash 30236248 290091073 211397 ] (C14H12) (46) ] (C17H19) (32) ] (C17H18) (17)

81 mdash 30260401 290310887 159088 ] (C12H13) (30) ] (C17H19) (27) ] (C17H18) (13) ](C30C32) (12)

82 mdash 303455 291085214 329164 ] (C21H2) (66) ] (C14H2) (28)83 mdash 30404085 291618149 40314 ] (C21H2) (55) ] (C30H32) (27) ] (C12H13) (7)84 mdash 30437899 291925696 263738 ] (C21H2) (98)85 mdash 30609167 293482854 503404 ] (C21H2) (85) ] (C30C32) (12)86 2931 30786333 295092629 824131 ] (C30C32) (95)

Organic Chemistry International 11

Table 3 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

87 mdash 30833975 295525341 441245 ] (C30C32) (93)88 mdash 30842781 295605315 369537 ] (C17H19) (67) ] (C17H18) (18) ] (C21H2) (9)

89 mdash 30889498 296029541 151201 ] (C21H2) (52) ] (C9H2) (14) ] (C12H13) (14) ] (C14H2)(8) ] (C17H19) (7)

90 2961 30930704 296403663 595099 ] (C17H19) (36) ] (C14H2) (28) ] (C17H20) (10) ](C21H2) (10) ] (C17H18) (8) ] (C9H2) (6)

91 3038 31462567 301227655 52018 ] (C1C4) (50) ] (C1H2) (31) ] (C1H3) (10)92 3069 31857999 304808243 34136 ] (C4H5) (57) ] (C4C6) (23) ] (C1C4) (14)93 3104 3237707 309500628 44771 ] (C1H2) (70) ] (C1H3) (11) ] (C4H5) (7)aAssignments and potential energy distribution (PED) (contributing ge 5) for vibrational normal mode Types of vibration ] stretching 120575 deformation oout-of-plane bending 120596 wagging y twisting 120588 rocking 120591 torsion w weak m medium sh shoulderbNormal mode number

Abso

rban

ce

Wavenumbers (cmminus1)

121

08060402

01200 1300 1400 1500 1600 1700 1800

17721295

13401357

1381

14081464

1619 1637 1686

1727

(a)

IR in

tens

ity (k

mm

ol) 50

40

30

20

10

0

Wavenumbers (cmminus1)1200 1250 1300 1350 1400 1450 1500 1550 1600 1650 1700 1750 1800

1244 12841301

1311

1307

134113731390

1394

1417

14631476

14841491

1656

1735

(b)

IR in

tens

ity (k

mm

ol) 50

40

30

20

10

0

Wavenumbers (cmminus1)

1227

1264

12421284

1266

12941302

13411373 1393

1419

14601476

14871489

16461731

1200 1250 1300 1350 1400 1450 1500 1550 1600 1650 1700 1750 1800

(c)

Figure 3 Comparison of the experimental IR (a) C=O and C=C stretching and CH bending region (1800ndash1200 cmminus1) with the appropriatetheoretical B3LYP6-311+Glowastlowast spectra ((b) and (c)) for s-cis and s-trans 2-ethylhexyl acrylate respectively

are well correlated to the calculated peaks in DFT for bothconformers see Tables 2 and 3

The shoulders in the infrared spectrum at 1025 1015 cmminus1of weak to medium intensities may be correlated to the bands1037 1015 cmminus1 for s-cis and 1015 988 cmminus1 for the s-trans

conformer These bands are ascribed to the CH out-of-planebending modes of the vinyl group

The remaining bands of weak intensity in the experimen-tal IR spectrum are 909 896 and 852 cmminus1 These bandsare close to the ones at 911 996 and 847 cmminus1 for the s-cis

12 Organic Chemistry International

121

08060402

0700 800 900 1000 1100 1200

727 770

811

952 869909 933

962 9841015 1025

1057

11161060

1191

Abso

rban

ce

Wavenumbers (cmminus1)

(a)

20

10

0

728776 783

825

848895

900911 940 975

1000

10131037

1008 1152 11581180

1016

1139

1156

1191

700 800 900 1000 1100 1200Wavenumbers (cmminus1)

IR in

tens

ity (k

mm

ol)

(b)

725

775783

827

846 896

900

940 965

993

1009

10131021

1066

10331051

1054

1079 11381156

1171

700 800 900 1000 1100 1200Wavenumbers (cmminus1)

20

10

0IR in

tens

ity (k

mm

ol)

(c)

Figure 4 Comparison of the experimental IR (a) CO stretching and CH bending region (1200ndash700 cmminus1) with the appropriate theoreticalB3LYP6-311+Glowastlowast spectra ((b) and (c)) for s-cis and s-trans 2-ethylhexyl acrylate respectively

conformation of the titlemolecule All the vibrational normalmodes in this region are not pure and the majority of themwere ascribed according to PED calculations to CH bending(for more details see Tables 2 and 3)

54 Region below 700 cmminus1 This spectral region includesthe bands associated with C=CndashC CndashOndashC O=CndashO OndashCndashC CndashCndashC and CndashCndashC bending and torsion modes aboutthe single bonds OndashC and CndashC The frequencies and PEDcalculations are presented in Tables 2 and 3 Comparing the23 first normal modes for the two conformers we notice thatthey have the same type of vibrational modes However thenormal modes 16 17 and 18 represent CCC bending in the s-trans andCHandCCC rockingmodes in the s-cis conformer

Due to the lack of experimental data on this region wecompare our calculated frequencies to some experimental IRbands of related molecules presented in the literature Thebands at 356 254 116 and 100 cmminus1 are close to the bandsat 349(A1015840) 244(A10158401015840) 114(A10158401015840) and 114 cmminus1 (A10158401015840) reported byDulce et al [28] From the same work the bands at 530 244114 and 114 cmminus1 belonging to A10158401015840 symmetry for the s-trans

methyl acrylate in liquid state are close to our calculatedbands in DFT at 542 244 116 and 106 cmminus1

6 Conclusions

Themid-IR spectrum of 2-ethylhexyl acrylate was measuredand interpreted with support of the DFTB3LYP6-311+Glowastlowastcalculated vibrational spectra followed by potential energydistribution analysis Assuming the s-cis and s-trans confor-mations we found two stable conformations close in theirenergies The fully optimized geometries of s-cis and s-transconformations by DFTB3LYP6-311+Glowastlowast were comparedwith the experimental and theoretical data presented in theliterature on the methyl acrylate molecule The compari-son shows a good agreement The experimental vibrationalspectrum is in good agreement with the theoretical spectracalculated for the two conformations Two neighbor bandsin the IR spectrum at 1619 and 1637 cmminus1 may be used ascharacteristic bands to locate and distinguish the existence ofone or both conformations

Organic Chemistry International 13

References

[1] M Salkind E H Riddle and R W Keefer ldquoAcrylates andmethacrylates ester manufacture and marketsrdquo Industrial ampEngineering Chemistry Research vol 51 no 11 pp 1328ndash13341959

[2] K S Anseth S M Newman and C N Bowman ldquoPolymericdental composites properties and reaction behavior of multi-methacrylate dental restorationsrdquo Advances in Polymer Sciencevol 122 pp 176ndash217 1995

[3] J G Kloosterboer ldquoNetwork formation by chain crosslink-ing photopolymerization and its application in electronicsrdquoAdvances in Polymer Science vol 84 pp 1ndash61 1988

[4] K Matyjaszewski Y Gnanou and L Leibler MacromolecularEngineering vol 1 Wiley-VCH Weinheim Germany 2007

[5] M Orgill B L Baker and N L Owen ldquoFTIR studies ofconformational isomerism in acrylates and acrylic acidsrdquo Spec-trochimica Acta A vol 55 no 5 pp 1021ndash1024 1999

[6] M Salkind ldquoReaches into the marketrdquo Industrial amp EngineeringChemistry Research vol 56 pp 62ndash110 1964

[7] E Takacs K Dajka and L Wojnarovits ldquoStudy of high-energyradiation initiated polymerization of butyl acrylaterdquo RadiationPhysics and Chemistry vol 63 no 1 pp 41ndash44 2002

[8] H Yu J Peng M Zhai J Li G Wei and J Qiao ldquoRadiation-induced copolymerization of styrenen-butyl acrylate in thepresence of ultra-fine powdered styrene-butadiene rubberrdquoRadiation Physics and Chemistry vol 76 no 11-12 pp 1736ndash1740 2007

[9] P F Canamero J Luis de la Fuente and M Fermandez-GarcıaldquoCuring kinetic study using a well-controlled multifunctionalcopolymer based on glycidyl methacrylaterdquo European PolymerJournal vol 45 no 9 pp 2665ndash2673 2009

[10] DMathew C P ReghunadhanNair and K N Ninan ldquoPendantcyanate functional vinyl polymers and imidophenolic-triazinesthereof synthesis and thermal propertiesrdquo European PolymerJournal vol 36 no 6 pp 1195ndash1208 2000

[11] S Mitra S Chattopadhyay S Sabharwal and A K BhowmickldquoElectron beam crosslinked gels-Preparation characterizationand their effect on the mechanical dynamic mechanical andrheological properties of rubbersrdquoRadiation Physics and Chem-istry vol 79 no 2 pp 289ndash296 2010

[12] P Canamero-Martınez M Fermandez-Garcıa and J Luis de laFuente ldquoRheological cure characterization of a polyfunctionalepoxy acrylic resinrdquo Reactive and Functional Polymers vol 70no 10 pp 761ndash766 2010

[13] F Chu T McKenna and S Lu ldquoCuring kinetics of an acrylicresinepoxy resin system using dynamic scanning calorimetryrdquoEuropean Polymer Journal vol 33 no 6 pp 837ndash840 1997

[14] M C Douskey M S Gebhard A V McCormick et alldquoSpectroscopic studies of a novel cyclic oligomer with pendantalkoxysilane groupsrdquo Progress in Organic Coatings vol 45 no2-3 pp 145ndash157 2002

[15] R J Day P A Lovell and A A Wazzan ldquoToughened car-bonepoxy composites made by using coreshell particlesrdquoComposites Science andTechnology vol 61 no 1 pp 41ndash56 2001

[16] K Bolton D G Lister and J Sheridan ldquoRotational isomerismbarrier to internal rotation and electric dipole moment ofacrylic acid bymicrowave spectroscopyrdquo Journal of the ChemicalSociety Faraday Transactions 2 vol 70 pp 113ndash123 1974

[17] S W Charles F C Cullen N L Owen and G A WilliamsldquoInfrared spectrum and rotational isomerism of acrylic acidrdquoJournal of Molecular Structure vol 157 no 1ndash3 pp 17ndash25 1987

[18] K Bolton N L Owen and J Sheridan ldquoMicrowave spectra ofrotational isomers of acrylic acidrdquoNature vol 218 no 5138 pp266ndash267 1968

[19] G Williams N L Owen and J Sheridan ldquoSpectroscopicstudies of some substitutedmethyl formatesmdashpart 1microwavespectra and internal rotation barriers of methyl-fluoroformate-propiolate -cyanoformate -acrylate and -acetaterdquo Transac-tions of the Faraday Society vol 67 pp 922ndash949 1971

[20] T Tsuji H Ito H Takeuchi and S Konaka ldquoMolecularstructure and conformation ofmethylmethacrylate determinedby gas electron diffractionrdquo Journal of Molecular Structure vol475 no 1 pp 55ndash63 1999

[21] T Egawa S Maekawa H Fujiwara Takeuchi H Takeuchi andS Konaka ldquoMolecular structure and conformation of methylacrylate a gas electron diffraction study augmented by ab initiocalculation and rotational constantsrdquo Molecular Structure andSpectroscopy vol 352 pp 193ndash201 1995

[22] A Virdi V P Gupta and A Sharma ldquoAb initio studies onconformation vibrational and electronic spectra of methylmethacrylaterdquo Journal ofMolecular Structure vol 634 no 5 pp53ndash65 2003

[23] B L Baker M Orgill N L Owen et al ldquoThe molecularconformation of methyl methacrylatemdashan infrared and abinitio studyrdquo Journal of Molecular Structure vol 356 no 2 pp95ndash104 1995

[24] A N Mitra and I Santhanan ldquoRelativistic qqq spectra fromBethe-Salpeter premisesrdquo Physics Letters B vol 104 no 1 pp62ndash66 1981

[25] K Fan and J E Boggs ldquoRotational isomerism of acrylic acidrdquoJournal of Molecular Structure vol 157 no 1ndash3 pp 31ndash41 1987

[26] P Carmona and J Moreno ldquoThe infrared spectra and structureof methyl acrylaterdquo Journal of Molecular Structure vol 82 no3-4 pp 177ndash185 1982

[27] R J Loncharich T R Schwartz and K N Houk ldquoTheoreticalstudies of conformations of acrolein acrylic acid methyl acry-late and their Lewis acid complexesrdquo Journal of the AmericanChemical Society vol 109 no 1 pp 14ndash23 1987

[28] M Dulce G Faria J J C Teixeira-Dias and R FaustoldquoVibrational spectra and structure of methyl trans-crotonaterdquoVibrational Spectroscopy vol 2 no 2-3 pp 43ndash60 1991

[29] J J C Teixeira-Dias and R Fausto ldquoMolecular structure ofmethyl acrylate the high energy s-trans-(CO) conformerrdquoJournal of Molecular Structure vol 282 no 1-2 pp 123ndash1291993

[30] A J Bowles W O George and D B Cunliffe-Jones ldquoConfor-mations of some120572120573-unsaturated carbonyl compoundsmdashpart IIinfrared and Raman spectra of methyl and ethyl acrylates andtranscrotonatesrdquo Journal of the Chemical Society B pp 1070ndash1075 1970

[31] A D Becke ldquoDensity-functional thermochemistry IIIThe roleof exact exchangerdquoThe Journal of Chemical Physics vol 98 no7 pp 5648ndash5652 1993

[32] C Lee W Yang and R G Parr ldquoDevelopment of the Colle-Salvetti correlation-energy formula into a functional of theelectron densityrdquo Physical Review B vol 37 no 2 pp 785ndash7891988

[33] H Yoshida K Takeda J Okamura A Ehara and H MatsuuraldquoA new approach to vibrational analysis of large molecules bydensity functional theory wavenumber-linear scalingmethodrdquoJournal of Physical Chemistry A vol 106 no 14 pp 3580ndash35862002

14 Organic Chemistry International

[34] H Yoshida A Ehara and H Matsuura ldquoDensity functionalvibrational analysis using wavenumber-linear scale factorsrdquoChemical Physics Letters vol 325 no 4 pp 477ndash483 2000

[35] M J Frisch G W Trucks H B Schlegel et al Gaussian 03Revision B 01 Gaussian Pittsburgh Pa USA 2003

[36] J M L Martin and C Van Alsenoy GAR2PED A Program toObtain a Potential Energy Distribution from a Gaussian ArchiveRecord University of Antwerp 2009

[37] P Pulay G Fogarasi F Pang and J E Boggs ldquoSystematicab initio gradient calculation of molecular geometries forceconstants and dipole moment derivativesrdquo Journal of theAmerican Chemical Society vol 101 no 10 pp 2550ndash2560 1979

[38] S Mishra D Chaturvedi N Kumar P Tandon and H WSiesler ldquoAn ab initio and DFT study of structure and vibrationalspectra of 120574 form of Oleic acid comparison to experimentaldatardquo Chemistry and Physics of Lipids vol 163 no 2 pp 207ndash217 2010

[39] W O George D V Hassid and W F Maddams ldquoConfor-mations of some 120572120573-unsaturated carbonyl compoundsmdashpartIII infrared solution spectra of methyl [2H3]methyl ethyland [2H5]ethyl acrylates and trans-crotonatesrdquo Journal of theChemical Society Perkin Transactions 2 no 4 pp 400ndash4041972

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Page 4: Research Article Molecular Structure and Vibrational Spectra ...e molecular geometry, vibrational frequencies, and infrared intensities have been calculated by using density functional

4 Organic Chemistry International

Table 1 Continued

Internal coordinatesLevel of theoryDFT6-311+Glowastlowast

s-cis EHA

s-cis methylacrylatea

DFT6-311+Glowastlowasts-trans EHA

s-trans methylacrylateb

C9 C12C14 108099 108115C12C14H15 108729 108720C12C14H16 108539 108544C12C14C17 115410 115400C14C17H18 111304 111345C14C17H19 110477 110478C14C17H20 112028 112001C9C12C21 111382 111384C12C21H22 109228 109231C12C21H23 109005 109019C12C21C24 114775 114824C21C24H25 108695 108731C21C24H26 110286 110291C21C24C27 113287 113308C24C27H28 109207 109229C24C27H29 109217 109208C24C27C30 113280 109208C27C30H31 111428 111428C27C30H32 111218 111209C27C30H33 111189 111202

Dihedral angles (∘)H3H2C1C4 180 minus179908H2C1C4H5 minus179977 179808H2C1C4C6 0037 0106C1C4C6O7 minus0166 178652C1C4C6O8 179844 minus1298C4C6O8C9 179896 179515C6O8C9H10 55606 55506C6O8C9H11 minus61282 minus61454C6O8C9C12 177303 177169O8C9 C12H13 55024 54463O8C9C12C14 171114 170547C9C12C14H15 61844 61568C9C12C14H16 minus53102 minus53378C9C12C14C17 minus175215 minus175516C12C14C17H18 56957 57249C12C14C17H19 176491 176782C12C14C17H20 minus63865 minus63596O8C9C12C21 minus63322 minus63915C9C12C21H22 minus96883 minus97147C9C12C21H23 18587 18279C9C12C21C24 139536 139298C12C21C24H25 minus59615 minus59061C12C21C24H26 56214 56717

Organic Chemistry International 5

Table 1 Continued

Internal coordinatesLevel of theoryDFT6-311+Glowastlowast

s-cis EHA

s-cis methylacrylatea

DFT6-311+Glowastlowasts-trans EHA

s-trans methylacrylateb

C12C21C24C27 178823 179360C21C24C27H28 minus58771 minus58768C21C24C27H29 56758 56753C21C24C27C30 179033 179029C24C27C30H31 179693 minus179983C24C27C30H32 minus60205 minus59888C24C27C30H33 59599 59917

aDetermined by a joint analysis of electron diffraction data and rotational constants [21]bDetermined by ab initio calculation at HF6ndash31Glowastlowast [20]

1

075

05

025

02800 2900 3000 3100 3200

Abso

rban

ce

Wavenumbers (cmminus1)

2861 28752931 2961

3038 3069 3104

(a)

100

80

60

40

20

0IR in

tens

ity (k

mm

ol)

2800 2900 3000 3100 3200Wavenumbers (cmminus1)

2884

2895

29113918

2936

2953

2963

3009 3048 3093

(b)

100

80

60

40

20

0IR in

tens

ity (k

mm

ol)

2800 2900 3000 3100 3200Wavenumbers (cmminus1)

28762880

2892

29102919

2934

2951

2963

3012 3048 3094

(c)

Figure 2 Comparison of the experimental IR (a) CH stretching region (3200ndash2800 cmminus1) with the appropriate theoretical DFTB3LYP6-311+Glowastlowast spectra ((b) and (c)) for s-cis and s-trans 2-ethylhexyl acrylate respectively

the butyl and the ethyl sides of the 2-ethylhexyl acrylatemolecule

52 The C=O and C=C Stretching and CH Bending Vibrations(1800ndash1200 cmminus1 Figure 3) In the IR spectrum (Figure 3(a))a very strong peak at 1727 cmminus1 represents the C=O stretching

band The simulated peaks are at 1735 and 1731 cmminus1 forthe s-cis and s-trans conformations these two frequenciescontribute to the experimental C=O stretching band

There are two C=C stretching bands in the experimentalspectra located at 1637 and 1619 cmminus1 of medium intensityThese bands are well reproduced by the theoretical bands at

6 Organic Chemistry International

Table 2 Frequencies and PEDs of s-cis 2-ethylhexyl acrylate

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

1 mdash 305017 307519 01860 120591 (O8C9) (63) 120591 (C9C12) (35)2 mdash 367273 3702484 19384 120591 (C9C12) (83) 120591 (O8C9) (17)3 mdash 482766 4865862 12435 120591 (C9C12) (98)

4 mdash 747391 7529828 00096 120588 (C30H3) (62) 120591 (C9C12) (17) 120591 (O8C9) (7) 120588 (C14H2)(7)

5 mdash 931493 9381827 07602 120591 (C9C12) (84) 120588 (C14H2) (15)6 mdash 996177 10032262 06102 120591 (C9C12) (76) 120591 (C9C12) (21)7 mdash 1159962 11678605 02949 120591 (C9C12) (94)8 mdash 1338201 13469244 07707 120591 (C9C12) (43) 120588 (C27H3) (31) 120588 (C9H2) (15)9 mdash 1461924 14711591 00469 120591 (C9C12) (58) 120588 (C9H2) (17) 120588 (C14H2) (16)10 mdash 2010708 20216112 18808 120591 (C9C12) (89) 120575 (C6O8C9) (5)11 mdash 2139423 21505753 27336 120591 (C9C12) (98)12 mdash 2341345 23527792 06986 120588 (C30H3) (94)13 mdash 2537618 25491989 12866 120588 (C30H3) (99)14 mdash 2654468 26660766 07334 120591 (C9C12) (83) 120588 (C30H3) (14)15 mdash 2851163 28627176 35548 120588 (C30H3) (78) 120591 (C9C12) (18)16 mdash 3157568 31687874 05814 120588 (C9H2) (89) 120588 (C17H3) (6)17 mdash 3551126 35614657 02263 120588 (C17H3) (36) 120588 (C9C12C14) (31) 120588 (C9H2) (19)

18 mdash 3759666 37693349 43994 120588 (C24C27C30) (27) 120588 (C9C12C14) (23) 120588 (C17H3) (17) 120575(C21C24C27) (10) 120588 (C9C12H13) (10) 120575 (C21H2) (8)

19 mdash 470318 47080422 06863 120588 (C9C12C21) (72) 120588 (C17H3) (11) 120588 (C9H2) (5)20 mdash 5120856 51226637 62054 120588 (C9C12C14) (80) 120588 (C9H2) (7) 120575 (C21C12C14) (6)21 mdash 5273488 52740376 01504 120588 (C9H2) (87) O (C6O7) (9)22 mdash 5339978 53399558 11100 120588 (C9C12C14) (77) 120588 (C6O8C9) (8)23 mdash 681189 67955184 31928 120588 (C9C12C14) (42) 120575 (O7C6C4) (42) 120588 (C6O8C9) (5)24 731 (m) 7312122 7288586 45137 120588 (C21C24C27) (99)25 748 (sh) 7795982 776474 10039 120588 (C27H2) (65) 120588 (C9C12C14) (18) 120588 (C14H2) (12)

26 770 (m) 7863101 78307298 16507 120588 (C27H2) (36) 120588 (C21H2) (32) 120588 (C14H2) (23) 120588(C17H3) (8)

27 811 (m) 8295925 82559191 249487 120588 (C9H2) (73) O (C6O7) (21) y (C1H2) (8)28 852 (w) 8523514 84792486 30736 120588 (C9C12C21) (82) 120588 (C9H2) (16)

29 896 (w) 9016472 89624016 10870 120588 (C9C12H21) (62) 120596 (C24H2) (16) y (C21H2) (9) 120575(C30H3) (8)

30 mdash 9068585 90134317 10553 120588 (C9C12H21) (86) 120588 (C9H2) (10)31 909 (w) 9172167 91148352 72928 120588 (C9H2) (58) 120596 (C27H2) (27) 120588 (O7C6O8) (12)32 933 (sh) 9478927 94149381 59570 120575 (C14C12H3) (50) 120596 (C27H2) (46)

33 962 (m) 9836705 97645643 251442 120588 (C9C12H13) (83) 120575 (C6O8C9) (21) y (C21H2) (14) y(C27H2) (11) y (C14H2) (11)

34 984 (m) 10069955 99922751 255334 120596 (C1H2) (84) y (C14H2) (10)

35 mdash 10169241 100891495 51103 120588 (C14H2) (41) 120588 (C9C12C21) (24) 120575 (C12C21C24) (23) 120588(C17H3) (7)

36 1015 (sh) 10232765 101511136 260306 o (C4H5) (99)37 mdash 10258451 101761651 19504 120575 (C9C12C14) (98) ] (C9O8) (5)38 1025 (sh) 10459956 103726182 278636 y (C24H2) (42) ] (C9C12) (42) ] (O8C9) (6)39 mdash 10621068 105295957 04109 120588 (C14C12H13) (83) ] (C27C30) (12)40 mdash 10659864 105673835 04863 ] (C14C17) (83) ] (C24C27) (11)41 mdash 10835238 107381387 16531 120596 (C9H2) (83) 120596 (C21H2) (15)42 1057 (m) 10894787 107960965 22238 120588 (C9H2) (84) 120596 (C27H2) (14)

Organic Chemistry International 7

Table 2 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

43 mdash 11505508 113898319 19252 120588 (C9C12H13) (96)

44 1116 (w) 11685589 115646723 118316 120575 (C12C21C24) (67) 120588 (C14C12H13) (9) 120588 (O8C9C12) (7)120575 (C14C12C21) (67)

45 1060 (sh) 11856606 117306145 00857 120575 (C9C12C14) (63) 120588 (C30H3) (26) 120575 (C12C14C17) (6)46 1191 12051044 11919167 6261232 120588 (C6C4H5) (87)47 mdash 12437853 12293901 03621 y (C21H2) (94) y (C27H2) (5)48 mdash 12586429 124377093 10505 120588 (C9H2) (76) 120596 (C21H2) (23)49 mdash 12817118 12660853 07178 y (C14H2) (55) 120596 (C21H2) (44)50 mdash 13003301 128408198 13337 120596 (C21H2) (93)

51 mdash 13179028 130105761 111581 120596 (C24H2) (24) 120588 (C9C12H13) (17) y (C14H2) (13) 120596(C27H2) (7) 120588 (C6O8C9) (5)

52 1272 13245992 130752384 683227 y (C27H2) (37) 120588 (C9C12H13) (29) y (C21H2) (22) y(C14H2) (6)

53 1295 13282386 131103753 60034 y (C27H2) (93)54 mdash 13381682 132062195 05711 y (C24H2) (70) y (C27H2) (28)55 1340 13610156 134266291 13124 120596 (C21H2) (78) 120596 (C9H2) (21)56 mdash 13812224 13621423 04732 120588 (C9C12C21) (78) 120596 (C21H2) (21)57 1357 13942309 137467547 33349 120596 (C9H2) (95)58 mdash 14045719 138463467 45032 120596 (C24H2) (95) 120596 (C21H2) (5)59 1381 14109338 139075996 73272 120596 (C21H2) (97)60 mdash 14141585 139386422 23703 120596 (C21H2) (99)61 mdash 14180649 139762426 04645 120596 (C21H2) (93) 120596 (C14H2) (6)62 1408 1437761 141657487 831633 120596 (C9H2) (49) 120596 (C21H2) (26) 120575 (CH2) (20)

63 mdash 14861635 146309161 10310 120575 (C21H2) (40) 120575 (C24H2) (20) 120575 (C12C21C24) (12) 120575(C14H2) (7)

64 mdash 14883957 1465235 10310 120575 (C27H2) (29) 120575 (C21H2) (28) 120575 (C24H2) (18) 120575(C12C21C24) (14) 120575 (C14H2) (10) 120575 (C27H2) (10)

65 mdash 1492293 146897685 13617 120575 (C21H2) (67) 120575 (C27H2) (11) 120575 (C14H2) (7)66 mdash 14999113 147628987 83925 120575 (C30H3) (88) 120575 (C27H2) (10)

67 mdash 15017672 147807111 43738 120575 (C21H2) (29) 120575 (C30H3) (28) 120575 (C24H2) (15) 120575(C21C12H13) (11) 120575 (C14H2) (6)

68 mdash 1503707 147993276 35078 120575 (C27H2) (31) 120575 (C21H2) (29) 120575 (C9H2) (18)

69 1464 15093473 148534511 99123 120575 (C17H3) (27) 120575 (C27H2) (26) 120575 (C21H2) (10) 120575(C12C21C24) (8) 120575 (C24H2) (7) 120575 (C12C14C21) (6)

70 mdash 15106836 148662726 108575 120575 (C21H2) (83) 120575 (C27H2) (10)

71 mdash 15154657 149121508 60184 120575 (C24H2) (42) 120575 (C21C24C27) (25) 120575 (C27H2) (13) 120575(C21H2) (10)

72 1637 16875503 165581242 269151 ] (C1C4) (87) 120575 (C1H2) (7)

73 1727 1770955 173524092 2434946 ] (C6O7) (80) 120575 (O8C9H12) (7) 120575 (C21H2) (5) ] (C4C6)(5)

74 mdash 29973914 287702371 27860 ] (C21H22) (45) ] (C14H2) (33) ] (C12H13) (14)75 mdash 29998142 287923075 17988 ] (C21H2) (76) ] (C24H2) (14)

76 mdash 30020159 288123622 138469 ] (C27H2) (33) ] (C24H2) (32) ] (C30H31) (22) ](C21H2) (6)

77 mdash 30058916 288476609 146381 ] (C21H2) (74) ] (C14H2) (14) ] (C12H13) (5)78 2861 30145745 289267245 457319 ] (C12H13) (63) ] (C30H31) (31)79 2875 30180275 289581595 559324 ] (C30H31) (98)80 mdash 30238407 290110723 222942 ] (C17H19) (58) ] (C17H18) (29)

81 mdash 30261436 290320306 164278 ] (C17H19) (32) ] (C14H2) (29) ] (C17H18) (15) ](C30C31) (8) ] (C21H2) (6)

82 mdash 30348324 291110906 351134 ] (C14H2) (96)

8 Organic Chemistry International

Table 2 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

83 mdash 30419158 291755246 160910 ] (C27H2) (38) ] (C9H2) (20) ] (C14H2) (19) ] (C21H2)(6) ] (C24H) (6)

84 mdash 30431697 29186929 145616 ] (C27H2) (47) ] (C9H2) (26) ] (C24H2) (10) ] (C14H2)(7)

85 mdash 3062906 293663657 465673 ] (C21H2) (55) ] (C27H2) (25) ] (C24H2) (9) ] (C12H13)(5)

86 2931 30788255 295110087 858987 ] (C27H2) (62) ] (C27H30) (10) ] 295503236 (C30H3)(9) ] (C9H2) (6) ] (C17H19) (6)

87 mdash 30831541 295503236 455349 ] (C30H31) (99)

88 mdash 30845244 295627682 351235 ] (C17H19) (67) ] (C17C19) (67) ] (C17C18) (17) ](C30H31) (15)

89 mdash 30879105 29593517 195239 ] (C9H2) (63) ] (O8C9) (16) ]-(C12H13) (11) ] (C17C19)(6)

90 2961 30931423 296410191 561433 ] (C17H19) (38) ] (C9H2) (26) ] (C17H20) (12) ](C14H2) (10) ] (C17H18) (9)

91 3038 31428663 300920422 51952 ] (C1C4) (45) ] (C1H2) (38) ] (C1H3) (9)92 mdash 3185092 304744188 32650 ] (C1H2) (95)93 3104 32359105 309338372 23617 ] (C4H5) (67) ] (C1H2) (22) ] (C1H3) (6)aAssignments and potential energy distribution (PED) (contributing ge 5) for vibrational normal mode Types of vibration ] stretching 120575 deformation oout-of-plane bending 120596 wagging y twisting 120588 rocking 120591 torsion w weak m medium sh shoulderbNormal mode number

1655 cmminus1 for s-cis conformer (Figure 3(b)) and 1647 cmminus1 forthe s-trans conformer (Figure 3(c)) The band at 1637 cmminus1may be used to definitely indicate that conformer with s-transarrangement of acrylic moiety is present or not in the liquid2-ethylhexyl acrylate

In the region from 1500 to 1200 cmminus1 in the experimen-tal spectrum (Figure 3) there are four bands of mediumintensity located at 1464 1408 1295 and 1272 cmminus1 Thebands of weak intensity of account of three are locatedat 1381 1357 and 1340 cmminus1 The calculated frequencies inthis region for the s-cis and s-trans conformations haveclose energies for each normal mode and the differencesdo not exceed 5 cmminus1 Based on the assignments reportedby Dulce et al [28] and our PED calculations we haveascribed the theoretical frequencies 1485 cmminus1 (s-cis) and1484 cmminus1 (s-trans) to the experimental band at 1464 cmminus1and they are representing a C

17H3symmetric bending The

calculated frequencies at 1479 1478 and 1476 cmminus1 may becontributed to the experimental band at 1464 cmminus1 due toits relatively large middle width of about 75 cmminus1 Mishra etal [38] have reported the experimental and the theoreticalIR spectra of 120574 form of oleic acid many peaks reported inthe region 1370 to 1220 cmminus1 for the CH

2carboxyl-sided

chain correspond approximately to those we found in ourspectrum from 1400 to 1200 cmminus1 and all of them may beassigned to CH

2deformation The assignment is based on

the bands intensities we found a good correlation betweenthe experimental and the theoretical spectra One shouldpoint out that the very intense bands predicted at 1267 and

1264 cmminus1 for s-trans form reproduce well the asymmetricshape of the experimental band at 1272 cmminus1 For bandsassignment see Tables 2 and 3

53 The CO Stretching and CH Bending Vibrations (1200ndash700 cmminus1 Figure 4) In this region in the IR spectrum thereis one very strong band at 1192 cmminus1 with weak shoulder at1160 cmminus1 and four medium intensity bands 1057 984 962shoulder at 933 and 811 cmminus1 The bands at 1116 1025 909896 852 770 and 727 cmminus1 (shoulder at 748 cmminus1) are ofweak intensity (Figure 4) Based on PEDs and intensities ofthe calculated frequencies we correlate the two intense bandsat 1192 and 1156 cmminus1 for the more stable and the less stableconformers to the band at 1191 cmminus1 in the experimentalIR spectrum The medium bands in IR spectrum are wellreproduced by the calculated peaks at 1079 999 976 941 and811 cmminus1 for the s-cis conformer and 1067 993 940 911 and828 cmminus1 for the s-trans conformer They may be ascribed toCH2rocking C

1H2wagging CCH rocking O

8C9 and C

1H2

twisting The peaks predicted by DFT at 728 and 783 cmminus1 ins-cis form and the peaks at 726 and 782 cmminus1 in the s-transformmay be correlated to the bands at 727 and 770 cmminus1 andthey are assigned to the CH

2deformations of the alkyl sides

of the title moleculeIn the IR spectra of 2-ethylhexyl acrylate reported in

this work there are a few bands with weak to very weakintensity which do not appear in the IR spectra of methylacrylate reported by Dulce et al [28] and George et al [39]These bands appear at 1157 1120 1052 and 1022 cmminus1 and they

Organic Chemistry International 9

Table 3 Frequencies and PEDs of s-trans 2-ethylhexyl acrylate

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

1 mdash 295569 2979981 13888 120591 (C21C24) (95)2 mdash 312922 3154848 12915 120591 (C21C24) (100)3 mdash 453002 4566086 00227 120591 (C21C24) (91) 120591 (O8C9) (6)4 mdash 69075 6959818 00113 120591 (C21C24) (98)5 mdash 916561 9231657 07304 120588 (C14H2) (64) 120591 (C9C12) (19) 120591 (C24C21) (15)6 mdash 106795 10753821 00788 120591 (C12C14) (92)7 mdash 116406 11719786 04606 120591 (O8C9) (90) 120591 (C21C24) (7)8 mdash 128002 12884855 07652 120591 (C21C24) (99)9 mdash 1377311 13862015 00737 120591 (C24C21) (94)10 mdash 1886176 18967867 24795 120591 (C24C21) (53) O (O8C9) (44)11 mdash 1964898 19756995 22280 120588 (C9H2) (82) 120591 (C9C12) (13)12 mdash 2346 23574391 17535 120588 (C30H3) (90) 120591 (C21C24) (7)13 mdash 2495865 25074252 32507 120588 (C30H3) (78) 120591 (C12C21) (19)14 mdash 2623636 26352416 12259 120588 (C9H2) (72) 120588 (C17H3) (22)15 mdash 2741636 27532362 05126 120591 (C12C21) (96)16 mdash 3352283 33631302 04554 120575 (C21C12C14) (93)17 mdash 3546136 355649 01655 120575 (C21C12C24) (95)18 mdash 406411 40725451 25402 120575 (C9C12C14) (92)19 mdash 4713032 47178287 10320 120588 (C9C12C14) (70) 120575 (C9C12C21) (12) 120588 (C14H2) (11)20 mdash 5098943 51009251 04733 y (C1H2) (86) O (C6O8) (12)

21 mdash 5140157 51418098 73067 120588 (C12C14C17) (38) 120588 (C9C12C21) (15) 120588 (C12C21) (14)120588 (C14C12H13) (13) 120588 (C1H2) (8) 120575 (C12C21C24) (7)

22 mdash 550859 55070531 22808 120588 (C9C12C14) (78) 120588 (C6O8C9) (9) 120588 (C1H2) (6)23 mdash 6360175 6349572 19146 120588 (O8C9C12) (97)24 727 (m) 7284338 72612214 43677 120588 (C9C12C21) (92)25 mdash 778027 77492902 06843 120588 (C9C12C21) (98)26 770 (m) 785397 78217532 18732 120588 (C21H2) (59) 120588 (C14H2) (36)27 811 (m) 8321364 82808904 215147 y (C1H2) (94) 120588 (C9H2) (5)

28 852 (w) 8501904 84580503 34731 120588 (C9C12C21) (47) 120588 (C9H2) (27) 120588 (C1H2) (15) ](C14C17) (5)

29 896 (w) 9017561 8963468 09206 120588 (C9C12C21) (73) 120588 (C21C24C27) (14)30 909 (w) 9065632 90105403 13451 120588 (C9C12C21) (46) 120588 (C9H2) (35) 120588 (C12C14C17) (9)31 933 (sh) 9170283 91129911 76343 120588 (O7C6O8) (86) 120588 (C9H2) (10)32 962 (m) 9470255 94064585 60649 120588 (C6O8C9) (99)33 mdash 9726775 96571834 70484 120588 (C6O8C9) (99)

34 984 (m) 10012212 99359199 344957 120596 (C1H2) (52) ] (C1C4) (15) 120575 (C4C6O8) (15) ] (C12C21)(15)

35 1015 (sh) 10171676 100915249 70006 ] (C12C21) (92)36 mdash 10219635 101383071 35045 ] (C21C24) (85) 120575 (C9C12O14) (9)37 1025 (sh) 10299052 102157589 185130 y (C1H2) (97)38 mdash 1040755 103215388 03554 ] (C21C24) (70) ] (C9C12) (14) y (C21H2) (5)39 mdash 10608287 105171458 55936 y (C21H2) (58) 120588 (C14C12H13) (29) 120588 (C14H2) (7)40 mdash 10640573 105485945 188097 ] (C21C24) (88) ] (C14C17) (8)41 1057 (m) 10767989 106726727 1926571 ] (C9O8) (82) ] (C14C17) (13)42 1060 (sh) 10895069 10796371 46500 120588 (C9H2) (40) 120575 (C9C12C21) (30) 120596 (C27H2) (25)43 1116 (w) 11506075 113903825 14631 120588 (C9C12H13) (51) 120575 (C9C12C21) (42)44 1191 11682621 115617915 32253 120588 (C14C12H13) (72) 120596 (C21H2) (16) 120588 (O8C9C12) (9)45 mdash 11850265 117244634 01695 120575 (C9C12C14) (94)

10 Organic Chemistry International

Table 3 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

46 mdash 1242923 122855525 17298 y (C21H2) (89)47 mdash 1258238 124337912 11546 120588 (C9C12C21) (35) 120596 (C21H2) (35) 120596 (C9H2) (27)48 mdash 12801017 126452842 779146 120596 (C21H2) (47) 120588 (C9C12C21) (37) 120588 (C9H2) (27)49 1272 1283202 126752616 3516365 120596 (C21H2) (60) y (C14H2) (27) y (C9H2) (10)50 mdash 12991286 128292094 44292 y (C9H2) (72) y (C21H2) (26)51 1295 13117811 129514505 72842 y (C14H2) (99)52 mdash 131875 130187577 68204 y (C14H2) (100)53 mdash 13264691 13093292 01479 y (C21H2) (97)54 mdash 13362199 131874163 04090 y (C24H2) (94) y (C21H2) (5)55 1340 1359997 134168063 10793 120596 (C21H2) (86) 120588 (C21C12C14) (7) 120596 (C9H2) (5)56 mdash 13800145 136097825 04801 120588 (C9C12C21) (43) 120575 (C9H12) (28) 120596 (C21H2) (25)

57 1357 13931134 137359902 28872 120596 (C9H2) (50) 120596 (C14H2) (23) 120575 (C21C12H13) (12) 120596(C21H2) (86)

58 mdash 14043849 138445461 09476 120596 (C21H2) (86) 120596 (C9H2) (12)59 mdash 14119509 139173911 08054 120596 (C9H2) (85) 120596 (C21H2) (14)60 1381 14145333 1394225 50233 120596 (C21H2) (54) 120596 (C9H2) (45)61 mdash 14173104 139689807 08100 120596 (C21H2) (89) 120596 (C9H2) (8)62 1408 14414398 142011302 305726 120596 (C9H2) (93) 120596 (C21H2) (5)

63 mdash 14831028 146015241 20326 120575 (C9H2) (38) 120575 (C21C12H13) (18) 120575 (C24C21C12) (15) 120575(C14H2) (13) 120575 (C24H2) (7) 120575 (C21H2) (6)

64 mdash 14876468 146451591 04300 120575 (C21C12H13) (33) 120575 (C27H2) (28) 120575 (C24H2) (20) 120575(C21H2) (10)

65 mdash 14916884 14683964 12432 120575 (C21H2) (54) 120575 (C9H2) (21) 120575 (C27H2) (11)

66 mdash 15000764 147644833 24692 120575 (C24H2) (32) 120575 (C21C12H13) (24) 120575 (C27H2) (8) 120575(C30H3) (8) 120575 (C21H2) (6)

67 mdash 1500718 147706413 70795 120575 (C30H3) (75) 120575 (C9H2) (11) 120575 (C27H2) (6)68 mdash 15025266 147879993 89950 120575 (C9H2) (74) 120575 (C17H3) (21)

69 1464 15081671 148421269 98400 120575 (C27H2) (26) 120575 (C30H3) (22) 120575 (C21H2) (14) 120575(C17H3) (14) 120575 (C24H2) (11)

70 mdash 15116225 148752807 105533 120575 (C21H2) (73) 120575 (C21C12H13) (6) 120575 (C24H2) (5) 120575(C17H3) (5)

71 mdash 1514069 14898752 56625 120575 (C24H2) (30) 120575 (C21H2) (29) 120575 (C21C24C27) (20) 120575(C27H2) (9)

72 1619 16787098 164738009 287096 ] (C1C4) (52) ] (C4C6) (22) 120575 (C9C12H13) (11) 120575(C21H2) (8)

73 1727 17668533 173134006 3155882 120575 (C9C12C21) (63) ] (C4C6) (16) 120575 (C21H2) (6) ](C6O7) (6)

74 mdash 2995932 287569419 20873 ] (C24H2) (35) ] (C14H2) (34) ] (C21H2) (25)

75 mdash 2998467 287800355 06759 ] (C24H2) (40) ] (C12H13) (29) ] (C21H2) (12) ](C14H2) (10)

76 mdash 3001649 288090203 135187 ] (C21H2) (92)77 mdash 30053152 288424116 132101 ] (C24H2) (87) ] (C24H2) (8)78 2861 3013385 289158948 585964 ] (C21H2) (45) ] (C30C32) (36) ] (C12H13) (12)79 2875 30178939 289569433 472871 ] (C30C32) (96)80 mdash 30236248 290091073 211397 ] (C14H12) (46) ] (C17H19) (32) ] (C17H18) (17)

81 mdash 30260401 290310887 159088 ] (C12H13) (30) ] (C17H19) (27) ] (C17H18) (13) ](C30C32) (12)

82 mdash 303455 291085214 329164 ] (C21H2) (66) ] (C14H2) (28)83 mdash 30404085 291618149 40314 ] (C21H2) (55) ] (C30H32) (27) ] (C12H13) (7)84 mdash 30437899 291925696 263738 ] (C21H2) (98)85 mdash 30609167 293482854 503404 ] (C21H2) (85) ] (C30C32) (12)86 2931 30786333 295092629 824131 ] (C30C32) (95)

Organic Chemistry International 11

Table 3 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

87 mdash 30833975 295525341 441245 ] (C30C32) (93)88 mdash 30842781 295605315 369537 ] (C17H19) (67) ] (C17H18) (18) ] (C21H2) (9)

89 mdash 30889498 296029541 151201 ] (C21H2) (52) ] (C9H2) (14) ] (C12H13) (14) ] (C14H2)(8) ] (C17H19) (7)

90 2961 30930704 296403663 595099 ] (C17H19) (36) ] (C14H2) (28) ] (C17H20) (10) ](C21H2) (10) ] (C17H18) (8) ] (C9H2) (6)

91 3038 31462567 301227655 52018 ] (C1C4) (50) ] (C1H2) (31) ] (C1H3) (10)92 3069 31857999 304808243 34136 ] (C4H5) (57) ] (C4C6) (23) ] (C1C4) (14)93 3104 3237707 309500628 44771 ] (C1H2) (70) ] (C1H3) (11) ] (C4H5) (7)aAssignments and potential energy distribution (PED) (contributing ge 5) for vibrational normal mode Types of vibration ] stretching 120575 deformation oout-of-plane bending 120596 wagging y twisting 120588 rocking 120591 torsion w weak m medium sh shoulderbNormal mode number

Abso

rban

ce

Wavenumbers (cmminus1)

121

08060402

01200 1300 1400 1500 1600 1700 1800

17721295

13401357

1381

14081464

1619 1637 1686

1727

(a)

IR in

tens

ity (k

mm

ol) 50

40

30

20

10

0

Wavenumbers (cmminus1)1200 1250 1300 1350 1400 1450 1500 1550 1600 1650 1700 1750 1800

1244 12841301

1311

1307

134113731390

1394

1417

14631476

14841491

1656

1735

(b)

IR in

tens

ity (k

mm

ol) 50

40

30

20

10

0

Wavenumbers (cmminus1)

1227

1264

12421284

1266

12941302

13411373 1393

1419

14601476

14871489

16461731

1200 1250 1300 1350 1400 1450 1500 1550 1600 1650 1700 1750 1800

(c)

Figure 3 Comparison of the experimental IR (a) C=O and C=C stretching and CH bending region (1800ndash1200 cmminus1) with the appropriatetheoretical B3LYP6-311+Glowastlowast spectra ((b) and (c)) for s-cis and s-trans 2-ethylhexyl acrylate respectively

are well correlated to the calculated peaks in DFT for bothconformers see Tables 2 and 3

The shoulders in the infrared spectrum at 1025 1015 cmminus1of weak to medium intensities may be correlated to the bands1037 1015 cmminus1 for s-cis and 1015 988 cmminus1 for the s-trans

conformer These bands are ascribed to the CH out-of-planebending modes of the vinyl group

The remaining bands of weak intensity in the experimen-tal IR spectrum are 909 896 and 852 cmminus1 These bandsare close to the ones at 911 996 and 847 cmminus1 for the s-cis

12 Organic Chemistry International

121

08060402

0700 800 900 1000 1100 1200

727 770

811

952 869909 933

962 9841015 1025

1057

11161060

1191

Abso

rban

ce

Wavenumbers (cmminus1)

(a)

20

10

0

728776 783

825

848895

900911 940 975

1000

10131037

1008 1152 11581180

1016

1139

1156

1191

700 800 900 1000 1100 1200Wavenumbers (cmminus1)

IR in

tens

ity (k

mm

ol)

(b)

725

775783

827

846 896

900

940 965

993

1009

10131021

1066

10331051

1054

1079 11381156

1171

700 800 900 1000 1100 1200Wavenumbers (cmminus1)

20

10

0IR in

tens

ity (k

mm

ol)

(c)

Figure 4 Comparison of the experimental IR (a) CO stretching and CH bending region (1200ndash700 cmminus1) with the appropriate theoreticalB3LYP6-311+Glowastlowast spectra ((b) and (c)) for s-cis and s-trans 2-ethylhexyl acrylate respectively

conformation of the titlemolecule All the vibrational normalmodes in this region are not pure and the majority of themwere ascribed according to PED calculations to CH bending(for more details see Tables 2 and 3)

54 Region below 700 cmminus1 This spectral region includesthe bands associated with C=CndashC CndashOndashC O=CndashO OndashCndashC CndashCndashC and CndashCndashC bending and torsion modes aboutthe single bonds OndashC and CndashC The frequencies and PEDcalculations are presented in Tables 2 and 3 Comparing the23 first normal modes for the two conformers we notice thatthey have the same type of vibrational modes However thenormal modes 16 17 and 18 represent CCC bending in the s-trans andCHandCCC rockingmodes in the s-cis conformer

Due to the lack of experimental data on this region wecompare our calculated frequencies to some experimental IRbands of related molecules presented in the literature Thebands at 356 254 116 and 100 cmminus1 are close to the bandsat 349(A1015840) 244(A10158401015840) 114(A10158401015840) and 114 cmminus1 (A10158401015840) reported byDulce et al [28] From the same work the bands at 530 244114 and 114 cmminus1 belonging to A10158401015840 symmetry for the s-trans

methyl acrylate in liquid state are close to our calculatedbands in DFT at 542 244 116 and 106 cmminus1

6 Conclusions

Themid-IR spectrum of 2-ethylhexyl acrylate was measuredand interpreted with support of the DFTB3LYP6-311+Glowastlowastcalculated vibrational spectra followed by potential energydistribution analysis Assuming the s-cis and s-trans confor-mations we found two stable conformations close in theirenergies The fully optimized geometries of s-cis and s-transconformations by DFTB3LYP6-311+Glowastlowast were comparedwith the experimental and theoretical data presented in theliterature on the methyl acrylate molecule The compari-son shows a good agreement The experimental vibrationalspectrum is in good agreement with the theoretical spectracalculated for the two conformations Two neighbor bandsin the IR spectrum at 1619 and 1637 cmminus1 may be used ascharacteristic bands to locate and distinguish the existence ofone or both conformations

Organic Chemistry International 13

References

[1] M Salkind E H Riddle and R W Keefer ldquoAcrylates andmethacrylates ester manufacture and marketsrdquo Industrial ampEngineering Chemistry Research vol 51 no 11 pp 1328ndash13341959

[2] K S Anseth S M Newman and C N Bowman ldquoPolymericdental composites properties and reaction behavior of multi-methacrylate dental restorationsrdquo Advances in Polymer Sciencevol 122 pp 176ndash217 1995

[3] J G Kloosterboer ldquoNetwork formation by chain crosslink-ing photopolymerization and its application in electronicsrdquoAdvances in Polymer Science vol 84 pp 1ndash61 1988

[4] K Matyjaszewski Y Gnanou and L Leibler MacromolecularEngineering vol 1 Wiley-VCH Weinheim Germany 2007

[5] M Orgill B L Baker and N L Owen ldquoFTIR studies ofconformational isomerism in acrylates and acrylic acidsrdquo Spec-trochimica Acta A vol 55 no 5 pp 1021ndash1024 1999

[6] M Salkind ldquoReaches into the marketrdquo Industrial amp EngineeringChemistry Research vol 56 pp 62ndash110 1964

[7] E Takacs K Dajka and L Wojnarovits ldquoStudy of high-energyradiation initiated polymerization of butyl acrylaterdquo RadiationPhysics and Chemistry vol 63 no 1 pp 41ndash44 2002

[8] H Yu J Peng M Zhai J Li G Wei and J Qiao ldquoRadiation-induced copolymerization of styrenen-butyl acrylate in thepresence of ultra-fine powdered styrene-butadiene rubberrdquoRadiation Physics and Chemistry vol 76 no 11-12 pp 1736ndash1740 2007

[9] P F Canamero J Luis de la Fuente and M Fermandez-GarcıaldquoCuring kinetic study using a well-controlled multifunctionalcopolymer based on glycidyl methacrylaterdquo European PolymerJournal vol 45 no 9 pp 2665ndash2673 2009

[10] DMathew C P ReghunadhanNair and K N Ninan ldquoPendantcyanate functional vinyl polymers and imidophenolic-triazinesthereof synthesis and thermal propertiesrdquo European PolymerJournal vol 36 no 6 pp 1195ndash1208 2000

[11] S Mitra S Chattopadhyay S Sabharwal and A K BhowmickldquoElectron beam crosslinked gels-Preparation characterizationand their effect on the mechanical dynamic mechanical andrheological properties of rubbersrdquoRadiation Physics and Chem-istry vol 79 no 2 pp 289ndash296 2010

[12] P Canamero-Martınez M Fermandez-Garcıa and J Luis de laFuente ldquoRheological cure characterization of a polyfunctionalepoxy acrylic resinrdquo Reactive and Functional Polymers vol 70no 10 pp 761ndash766 2010

[13] F Chu T McKenna and S Lu ldquoCuring kinetics of an acrylicresinepoxy resin system using dynamic scanning calorimetryrdquoEuropean Polymer Journal vol 33 no 6 pp 837ndash840 1997

[14] M C Douskey M S Gebhard A V McCormick et alldquoSpectroscopic studies of a novel cyclic oligomer with pendantalkoxysilane groupsrdquo Progress in Organic Coatings vol 45 no2-3 pp 145ndash157 2002

[15] R J Day P A Lovell and A A Wazzan ldquoToughened car-bonepoxy composites made by using coreshell particlesrdquoComposites Science andTechnology vol 61 no 1 pp 41ndash56 2001

[16] K Bolton D G Lister and J Sheridan ldquoRotational isomerismbarrier to internal rotation and electric dipole moment ofacrylic acid bymicrowave spectroscopyrdquo Journal of the ChemicalSociety Faraday Transactions 2 vol 70 pp 113ndash123 1974

[17] S W Charles F C Cullen N L Owen and G A WilliamsldquoInfrared spectrum and rotational isomerism of acrylic acidrdquoJournal of Molecular Structure vol 157 no 1ndash3 pp 17ndash25 1987

[18] K Bolton N L Owen and J Sheridan ldquoMicrowave spectra ofrotational isomers of acrylic acidrdquoNature vol 218 no 5138 pp266ndash267 1968

[19] G Williams N L Owen and J Sheridan ldquoSpectroscopicstudies of some substitutedmethyl formatesmdashpart 1microwavespectra and internal rotation barriers of methyl-fluoroformate-propiolate -cyanoformate -acrylate and -acetaterdquo Transac-tions of the Faraday Society vol 67 pp 922ndash949 1971

[20] T Tsuji H Ito H Takeuchi and S Konaka ldquoMolecularstructure and conformation ofmethylmethacrylate determinedby gas electron diffractionrdquo Journal of Molecular Structure vol475 no 1 pp 55ndash63 1999

[21] T Egawa S Maekawa H Fujiwara Takeuchi H Takeuchi andS Konaka ldquoMolecular structure and conformation of methylacrylate a gas electron diffraction study augmented by ab initiocalculation and rotational constantsrdquo Molecular Structure andSpectroscopy vol 352 pp 193ndash201 1995

[22] A Virdi V P Gupta and A Sharma ldquoAb initio studies onconformation vibrational and electronic spectra of methylmethacrylaterdquo Journal ofMolecular Structure vol 634 no 5 pp53ndash65 2003

[23] B L Baker M Orgill N L Owen et al ldquoThe molecularconformation of methyl methacrylatemdashan infrared and abinitio studyrdquo Journal of Molecular Structure vol 356 no 2 pp95ndash104 1995

[24] A N Mitra and I Santhanan ldquoRelativistic qqq spectra fromBethe-Salpeter premisesrdquo Physics Letters B vol 104 no 1 pp62ndash66 1981

[25] K Fan and J E Boggs ldquoRotational isomerism of acrylic acidrdquoJournal of Molecular Structure vol 157 no 1ndash3 pp 31ndash41 1987

[26] P Carmona and J Moreno ldquoThe infrared spectra and structureof methyl acrylaterdquo Journal of Molecular Structure vol 82 no3-4 pp 177ndash185 1982

[27] R J Loncharich T R Schwartz and K N Houk ldquoTheoreticalstudies of conformations of acrolein acrylic acid methyl acry-late and their Lewis acid complexesrdquo Journal of the AmericanChemical Society vol 109 no 1 pp 14ndash23 1987

[28] M Dulce G Faria J J C Teixeira-Dias and R FaustoldquoVibrational spectra and structure of methyl trans-crotonaterdquoVibrational Spectroscopy vol 2 no 2-3 pp 43ndash60 1991

[29] J J C Teixeira-Dias and R Fausto ldquoMolecular structure ofmethyl acrylate the high energy s-trans-(CO) conformerrdquoJournal of Molecular Structure vol 282 no 1-2 pp 123ndash1291993

[30] A J Bowles W O George and D B Cunliffe-Jones ldquoConfor-mations of some120572120573-unsaturated carbonyl compoundsmdashpart IIinfrared and Raman spectra of methyl and ethyl acrylates andtranscrotonatesrdquo Journal of the Chemical Society B pp 1070ndash1075 1970

[31] A D Becke ldquoDensity-functional thermochemistry IIIThe roleof exact exchangerdquoThe Journal of Chemical Physics vol 98 no7 pp 5648ndash5652 1993

[32] C Lee W Yang and R G Parr ldquoDevelopment of the Colle-Salvetti correlation-energy formula into a functional of theelectron densityrdquo Physical Review B vol 37 no 2 pp 785ndash7891988

[33] H Yoshida K Takeda J Okamura A Ehara and H MatsuuraldquoA new approach to vibrational analysis of large molecules bydensity functional theory wavenumber-linear scalingmethodrdquoJournal of Physical Chemistry A vol 106 no 14 pp 3580ndash35862002

14 Organic Chemistry International

[34] H Yoshida A Ehara and H Matsuura ldquoDensity functionalvibrational analysis using wavenumber-linear scale factorsrdquoChemical Physics Letters vol 325 no 4 pp 477ndash483 2000

[35] M J Frisch G W Trucks H B Schlegel et al Gaussian 03Revision B 01 Gaussian Pittsburgh Pa USA 2003

[36] J M L Martin and C Van Alsenoy GAR2PED A Program toObtain a Potential Energy Distribution from a Gaussian ArchiveRecord University of Antwerp 2009

[37] P Pulay G Fogarasi F Pang and J E Boggs ldquoSystematicab initio gradient calculation of molecular geometries forceconstants and dipole moment derivativesrdquo Journal of theAmerican Chemical Society vol 101 no 10 pp 2550ndash2560 1979

[38] S Mishra D Chaturvedi N Kumar P Tandon and H WSiesler ldquoAn ab initio and DFT study of structure and vibrationalspectra of 120574 form of Oleic acid comparison to experimentaldatardquo Chemistry and Physics of Lipids vol 163 no 2 pp 207ndash217 2010

[39] W O George D V Hassid and W F Maddams ldquoConfor-mations of some 120572120573-unsaturated carbonyl compoundsmdashpartIII infrared solution spectra of methyl [2H3]methyl ethyland [2H5]ethyl acrylates and trans-crotonatesrdquo Journal of theChemical Society Perkin Transactions 2 no 4 pp 400ndash4041972

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

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CatalystsJournal of

Page 5: Research Article Molecular Structure and Vibrational Spectra ...e molecular geometry, vibrational frequencies, and infrared intensities have been calculated by using density functional

Organic Chemistry International 5

Table 1 Continued

Internal coordinatesLevel of theoryDFT6-311+Glowastlowast

s-cis EHA

s-cis methylacrylatea

DFT6-311+Glowastlowasts-trans EHA

s-trans methylacrylateb

C12C21C24C27 178823 179360C21C24C27H28 minus58771 minus58768C21C24C27H29 56758 56753C21C24C27C30 179033 179029C24C27C30H31 179693 minus179983C24C27C30H32 minus60205 minus59888C24C27C30H33 59599 59917

aDetermined by a joint analysis of electron diffraction data and rotational constants [21]bDetermined by ab initio calculation at HF6ndash31Glowastlowast [20]

1

075

05

025

02800 2900 3000 3100 3200

Abso

rban

ce

Wavenumbers (cmminus1)

2861 28752931 2961

3038 3069 3104

(a)

100

80

60

40

20

0IR in

tens

ity (k

mm

ol)

2800 2900 3000 3100 3200Wavenumbers (cmminus1)

2884

2895

29113918

2936

2953

2963

3009 3048 3093

(b)

100

80

60

40

20

0IR in

tens

ity (k

mm

ol)

2800 2900 3000 3100 3200Wavenumbers (cmminus1)

28762880

2892

29102919

2934

2951

2963

3012 3048 3094

(c)

Figure 2 Comparison of the experimental IR (a) CH stretching region (3200ndash2800 cmminus1) with the appropriate theoretical DFTB3LYP6-311+Glowastlowast spectra ((b) and (c)) for s-cis and s-trans 2-ethylhexyl acrylate respectively

the butyl and the ethyl sides of the 2-ethylhexyl acrylatemolecule

52 The C=O and C=C Stretching and CH Bending Vibrations(1800ndash1200 cmminus1 Figure 3) In the IR spectrum (Figure 3(a))a very strong peak at 1727 cmminus1 represents the C=O stretching

band The simulated peaks are at 1735 and 1731 cmminus1 forthe s-cis and s-trans conformations these two frequenciescontribute to the experimental C=O stretching band

There are two C=C stretching bands in the experimentalspectra located at 1637 and 1619 cmminus1 of medium intensityThese bands are well reproduced by the theoretical bands at

6 Organic Chemistry International

Table 2 Frequencies and PEDs of s-cis 2-ethylhexyl acrylate

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

1 mdash 305017 307519 01860 120591 (O8C9) (63) 120591 (C9C12) (35)2 mdash 367273 3702484 19384 120591 (C9C12) (83) 120591 (O8C9) (17)3 mdash 482766 4865862 12435 120591 (C9C12) (98)

4 mdash 747391 7529828 00096 120588 (C30H3) (62) 120591 (C9C12) (17) 120591 (O8C9) (7) 120588 (C14H2)(7)

5 mdash 931493 9381827 07602 120591 (C9C12) (84) 120588 (C14H2) (15)6 mdash 996177 10032262 06102 120591 (C9C12) (76) 120591 (C9C12) (21)7 mdash 1159962 11678605 02949 120591 (C9C12) (94)8 mdash 1338201 13469244 07707 120591 (C9C12) (43) 120588 (C27H3) (31) 120588 (C9H2) (15)9 mdash 1461924 14711591 00469 120591 (C9C12) (58) 120588 (C9H2) (17) 120588 (C14H2) (16)10 mdash 2010708 20216112 18808 120591 (C9C12) (89) 120575 (C6O8C9) (5)11 mdash 2139423 21505753 27336 120591 (C9C12) (98)12 mdash 2341345 23527792 06986 120588 (C30H3) (94)13 mdash 2537618 25491989 12866 120588 (C30H3) (99)14 mdash 2654468 26660766 07334 120591 (C9C12) (83) 120588 (C30H3) (14)15 mdash 2851163 28627176 35548 120588 (C30H3) (78) 120591 (C9C12) (18)16 mdash 3157568 31687874 05814 120588 (C9H2) (89) 120588 (C17H3) (6)17 mdash 3551126 35614657 02263 120588 (C17H3) (36) 120588 (C9C12C14) (31) 120588 (C9H2) (19)

18 mdash 3759666 37693349 43994 120588 (C24C27C30) (27) 120588 (C9C12C14) (23) 120588 (C17H3) (17) 120575(C21C24C27) (10) 120588 (C9C12H13) (10) 120575 (C21H2) (8)

19 mdash 470318 47080422 06863 120588 (C9C12C21) (72) 120588 (C17H3) (11) 120588 (C9H2) (5)20 mdash 5120856 51226637 62054 120588 (C9C12C14) (80) 120588 (C9H2) (7) 120575 (C21C12C14) (6)21 mdash 5273488 52740376 01504 120588 (C9H2) (87) O (C6O7) (9)22 mdash 5339978 53399558 11100 120588 (C9C12C14) (77) 120588 (C6O8C9) (8)23 mdash 681189 67955184 31928 120588 (C9C12C14) (42) 120575 (O7C6C4) (42) 120588 (C6O8C9) (5)24 731 (m) 7312122 7288586 45137 120588 (C21C24C27) (99)25 748 (sh) 7795982 776474 10039 120588 (C27H2) (65) 120588 (C9C12C14) (18) 120588 (C14H2) (12)

26 770 (m) 7863101 78307298 16507 120588 (C27H2) (36) 120588 (C21H2) (32) 120588 (C14H2) (23) 120588(C17H3) (8)

27 811 (m) 8295925 82559191 249487 120588 (C9H2) (73) O (C6O7) (21) y (C1H2) (8)28 852 (w) 8523514 84792486 30736 120588 (C9C12C21) (82) 120588 (C9H2) (16)

29 896 (w) 9016472 89624016 10870 120588 (C9C12H21) (62) 120596 (C24H2) (16) y (C21H2) (9) 120575(C30H3) (8)

30 mdash 9068585 90134317 10553 120588 (C9C12H21) (86) 120588 (C9H2) (10)31 909 (w) 9172167 91148352 72928 120588 (C9H2) (58) 120596 (C27H2) (27) 120588 (O7C6O8) (12)32 933 (sh) 9478927 94149381 59570 120575 (C14C12H3) (50) 120596 (C27H2) (46)

33 962 (m) 9836705 97645643 251442 120588 (C9C12H13) (83) 120575 (C6O8C9) (21) y (C21H2) (14) y(C27H2) (11) y (C14H2) (11)

34 984 (m) 10069955 99922751 255334 120596 (C1H2) (84) y (C14H2) (10)

35 mdash 10169241 100891495 51103 120588 (C14H2) (41) 120588 (C9C12C21) (24) 120575 (C12C21C24) (23) 120588(C17H3) (7)

36 1015 (sh) 10232765 101511136 260306 o (C4H5) (99)37 mdash 10258451 101761651 19504 120575 (C9C12C14) (98) ] (C9O8) (5)38 1025 (sh) 10459956 103726182 278636 y (C24H2) (42) ] (C9C12) (42) ] (O8C9) (6)39 mdash 10621068 105295957 04109 120588 (C14C12H13) (83) ] (C27C30) (12)40 mdash 10659864 105673835 04863 ] (C14C17) (83) ] (C24C27) (11)41 mdash 10835238 107381387 16531 120596 (C9H2) (83) 120596 (C21H2) (15)42 1057 (m) 10894787 107960965 22238 120588 (C9H2) (84) 120596 (C27H2) (14)

Organic Chemistry International 7

Table 2 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

43 mdash 11505508 113898319 19252 120588 (C9C12H13) (96)

44 1116 (w) 11685589 115646723 118316 120575 (C12C21C24) (67) 120588 (C14C12H13) (9) 120588 (O8C9C12) (7)120575 (C14C12C21) (67)

45 1060 (sh) 11856606 117306145 00857 120575 (C9C12C14) (63) 120588 (C30H3) (26) 120575 (C12C14C17) (6)46 1191 12051044 11919167 6261232 120588 (C6C4H5) (87)47 mdash 12437853 12293901 03621 y (C21H2) (94) y (C27H2) (5)48 mdash 12586429 124377093 10505 120588 (C9H2) (76) 120596 (C21H2) (23)49 mdash 12817118 12660853 07178 y (C14H2) (55) 120596 (C21H2) (44)50 mdash 13003301 128408198 13337 120596 (C21H2) (93)

51 mdash 13179028 130105761 111581 120596 (C24H2) (24) 120588 (C9C12H13) (17) y (C14H2) (13) 120596(C27H2) (7) 120588 (C6O8C9) (5)

52 1272 13245992 130752384 683227 y (C27H2) (37) 120588 (C9C12H13) (29) y (C21H2) (22) y(C14H2) (6)

53 1295 13282386 131103753 60034 y (C27H2) (93)54 mdash 13381682 132062195 05711 y (C24H2) (70) y (C27H2) (28)55 1340 13610156 134266291 13124 120596 (C21H2) (78) 120596 (C9H2) (21)56 mdash 13812224 13621423 04732 120588 (C9C12C21) (78) 120596 (C21H2) (21)57 1357 13942309 137467547 33349 120596 (C9H2) (95)58 mdash 14045719 138463467 45032 120596 (C24H2) (95) 120596 (C21H2) (5)59 1381 14109338 139075996 73272 120596 (C21H2) (97)60 mdash 14141585 139386422 23703 120596 (C21H2) (99)61 mdash 14180649 139762426 04645 120596 (C21H2) (93) 120596 (C14H2) (6)62 1408 1437761 141657487 831633 120596 (C9H2) (49) 120596 (C21H2) (26) 120575 (CH2) (20)

63 mdash 14861635 146309161 10310 120575 (C21H2) (40) 120575 (C24H2) (20) 120575 (C12C21C24) (12) 120575(C14H2) (7)

64 mdash 14883957 1465235 10310 120575 (C27H2) (29) 120575 (C21H2) (28) 120575 (C24H2) (18) 120575(C12C21C24) (14) 120575 (C14H2) (10) 120575 (C27H2) (10)

65 mdash 1492293 146897685 13617 120575 (C21H2) (67) 120575 (C27H2) (11) 120575 (C14H2) (7)66 mdash 14999113 147628987 83925 120575 (C30H3) (88) 120575 (C27H2) (10)

67 mdash 15017672 147807111 43738 120575 (C21H2) (29) 120575 (C30H3) (28) 120575 (C24H2) (15) 120575(C21C12H13) (11) 120575 (C14H2) (6)

68 mdash 1503707 147993276 35078 120575 (C27H2) (31) 120575 (C21H2) (29) 120575 (C9H2) (18)

69 1464 15093473 148534511 99123 120575 (C17H3) (27) 120575 (C27H2) (26) 120575 (C21H2) (10) 120575(C12C21C24) (8) 120575 (C24H2) (7) 120575 (C12C14C21) (6)

70 mdash 15106836 148662726 108575 120575 (C21H2) (83) 120575 (C27H2) (10)

71 mdash 15154657 149121508 60184 120575 (C24H2) (42) 120575 (C21C24C27) (25) 120575 (C27H2) (13) 120575(C21H2) (10)

72 1637 16875503 165581242 269151 ] (C1C4) (87) 120575 (C1H2) (7)

73 1727 1770955 173524092 2434946 ] (C6O7) (80) 120575 (O8C9H12) (7) 120575 (C21H2) (5) ] (C4C6)(5)

74 mdash 29973914 287702371 27860 ] (C21H22) (45) ] (C14H2) (33) ] (C12H13) (14)75 mdash 29998142 287923075 17988 ] (C21H2) (76) ] (C24H2) (14)

76 mdash 30020159 288123622 138469 ] (C27H2) (33) ] (C24H2) (32) ] (C30H31) (22) ](C21H2) (6)

77 mdash 30058916 288476609 146381 ] (C21H2) (74) ] (C14H2) (14) ] (C12H13) (5)78 2861 30145745 289267245 457319 ] (C12H13) (63) ] (C30H31) (31)79 2875 30180275 289581595 559324 ] (C30H31) (98)80 mdash 30238407 290110723 222942 ] (C17H19) (58) ] (C17H18) (29)

81 mdash 30261436 290320306 164278 ] (C17H19) (32) ] (C14H2) (29) ] (C17H18) (15) ](C30C31) (8) ] (C21H2) (6)

82 mdash 30348324 291110906 351134 ] (C14H2) (96)

8 Organic Chemistry International

Table 2 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

83 mdash 30419158 291755246 160910 ] (C27H2) (38) ] (C9H2) (20) ] (C14H2) (19) ] (C21H2)(6) ] (C24H) (6)

84 mdash 30431697 29186929 145616 ] (C27H2) (47) ] (C9H2) (26) ] (C24H2) (10) ] (C14H2)(7)

85 mdash 3062906 293663657 465673 ] (C21H2) (55) ] (C27H2) (25) ] (C24H2) (9) ] (C12H13)(5)

86 2931 30788255 295110087 858987 ] (C27H2) (62) ] (C27H30) (10) ] 295503236 (C30H3)(9) ] (C9H2) (6) ] (C17H19) (6)

87 mdash 30831541 295503236 455349 ] (C30H31) (99)

88 mdash 30845244 295627682 351235 ] (C17H19) (67) ] (C17C19) (67) ] (C17C18) (17) ](C30H31) (15)

89 mdash 30879105 29593517 195239 ] (C9H2) (63) ] (O8C9) (16) ]-(C12H13) (11) ] (C17C19)(6)

90 2961 30931423 296410191 561433 ] (C17H19) (38) ] (C9H2) (26) ] (C17H20) (12) ](C14H2) (10) ] (C17H18) (9)

91 3038 31428663 300920422 51952 ] (C1C4) (45) ] (C1H2) (38) ] (C1H3) (9)92 mdash 3185092 304744188 32650 ] (C1H2) (95)93 3104 32359105 309338372 23617 ] (C4H5) (67) ] (C1H2) (22) ] (C1H3) (6)aAssignments and potential energy distribution (PED) (contributing ge 5) for vibrational normal mode Types of vibration ] stretching 120575 deformation oout-of-plane bending 120596 wagging y twisting 120588 rocking 120591 torsion w weak m medium sh shoulderbNormal mode number

1655 cmminus1 for s-cis conformer (Figure 3(b)) and 1647 cmminus1 forthe s-trans conformer (Figure 3(c)) The band at 1637 cmminus1may be used to definitely indicate that conformer with s-transarrangement of acrylic moiety is present or not in the liquid2-ethylhexyl acrylate

In the region from 1500 to 1200 cmminus1 in the experimen-tal spectrum (Figure 3) there are four bands of mediumintensity located at 1464 1408 1295 and 1272 cmminus1 Thebands of weak intensity of account of three are locatedat 1381 1357 and 1340 cmminus1 The calculated frequencies inthis region for the s-cis and s-trans conformations haveclose energies for each normal mode and the differencesdo not exceed 5 cmminus1 Based on the assignments reportedby Dulce et al [28] and our PED calculations we haveascribed the theoretical frequencies 1485 cmminus1 (s-cis) and1484 cmminus1 (s-trans) to the experimental band at 1464 cmminus1and they are representing a C

17H3symmetric bending The

calculated frequencies at 1479 1478 and 1476 cmminus1 may becontributed to the experimental band at 1464 cmminus1 due toits relatively large middle width of about 75 cmminus1 Mishra etal [38] have reported the experimental and the theoreticalIR spectra of 120574 form of oleic acid many peaks reported inthe region 1370 to 1220 cmminus1 for the CH

2carboxyl-sided

chain correspond approximately to those we found in ourspectrum from 1400 to 1200 cmminus1 and all of them may beassigned to CH

2deformation The assignment is based on

the bands intensities we found a good correlation betweenthe experimental and the theoretical spectra One shouldpoint out that the very intense bands predicted at 1267 and

1264 cmminus1 for s-trans form reproduce well the asymmetricshape of the experimental band at 1272 cmminus1 For bandsassignment see Tables 2 and 3

53 The CO Stretching and CH Bending Vibrations (1200ndash700 cmminus1 Figure 4) In this region in the IR spectrum thereis one very strong band at 1192 cmminus1 with weak shoulder at1160 cmminus1 and four medium intensity bands 1057 984 962shoulder at 933 and 811 cmminus1 The bands at 1116 1025 909896 852 770 and 727 cmminus1 (shoulder at 748 cmminus1) are ofweak intensity (Figure 4) Based on PEDs and intensities ofthe calculated frequencies we correlate the two intense bandsat 1192 and 1156 cmminus1 for the more stable and the less stableconformers to the band at 1191 cmminus1 in the experimentalIR spectrum The medium bands in IR spectrum are wellreproduced by the calculated peaks at 1079 999 976 941 and811 cmminus1 for the s-cis conformer and 1067 993 940 911 and828 cmminus1 for the s-trans conformer They may be ascribed toCH2rocking C

1H2wagging CCH rocking O

8C9 and C

1H2

twisting The peaks predicted by DFT at 728 and 783 cmminus1 ins-cis form and the peaks at 726 and 782 cmminus1 in the s-transformmay be correlated to the bands at 727 and 770 cmminus1 andthey are assigned to the CH

2deformations of the alkyl sides

of the title moleculeIn the IR spectra of 2-ethylhexyl acrylate reported in

this work there are a few bands with weak to very weakintensity which do not appear in the IR spectra of methylacrylate reported by Dulce et al [28] and George et al [39]These bands appear at 1157 1120 1052 and 1022 cmminus1 and they

Organic Chemistry International 9

Table 3 Frequencies and PEDs of s-trans 2-ethylhexyl acrylate

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

1 mdash 295569 2979981 13888 120591 (C21C24) (95)2 mdash 312922 3154848 12915 120591 (C21C24) (100)3 mdash 453002 4566086 00227 120591 (C21C24) (91) 120591 (O8C9) (6)4 mdash 69075 6959818 00113 120591 (C21C24) (98)5 mdash 916561 9231657 07304 120588 (C14H2) (64) 120591 (C9C12) (19) 120591 (C24C21) (15)6 mdash 106795 10753821 00788 120591 (C12C14) (92)7 mdash 116406 11719786 04606 120591 (O8C9) (90) 120591 (C21C24) (7)8 mdash 128002 12884855 07652 120591 (C21C24) (99)9 mdash 1377311 13862015 00737 120591 (C24C21) (94)10 mdash 1886176 18967867 24795 120591 (C24C21) (53) O (O8C9) (44)11 mdash 1964898 19756995 22280 120588 (C9H2) (82) 120591 (C9C12) (13)12 mdash 2346 23574391 17535 120588 (C30H3) (90) 120591 (C21C24) (7)13 mdash 2495865 25074252 32507 120588 (C30H3) (78) 120591 (C12C21) (19)14 mdash 2623636 26352416 12259 120588 (C9H2) (72) 120588 (C17H3) (22)15 mdash 2741636 27532362 05126 120591 (C12C21) (96)16 mdash 3352283 33631302 04554 120575 (C21C12C14) (93)17 mdash 3546136 355649 01655 120575 (C21C12C24) (95)18 mdash 406411 40725451 25402 120575 (C9C12C14) (92)19 mdash 4713032 47178287 10320 120588 (C9C12C14) (70) 120575 (C9C12C21) (12) 120588 (C14H2) (11)20 mdash 5098943 51009251 04733 y (C1H2) (86) O (C6O8) (12)

21 mdash 5140157 51418098 73067 120588 (C12C14C17) (38) 120588 (C9C12C21) (15) 120588 (C12C21) (14)120588 (C14C12H13) (13) 120588 (C1H2) (8) 120575 (C12C21C24) (7)

22 mdash 550859 55070531 22808 120588 (C9C12C14) (78) 120588 (C6O8C9) (9) 120588 (C1H2) (6)23 mdash 6360175 6349572 19146 120588 (O8C9C12) (97)24 727 (m) 7284338 72612214 43677 120588 (C9C12C21) (92)25 mdash 778027 77492902 06843 120588 (C9C12C21) (98)26 770 (m) 785397 78217532 18732 120588 (C21H2) (59) 120588 (C14H2) (36)27 811 (m) 8321364 82808904 215147 y (C1H2) (94) 120588 (C9H2) (5)

28 852 (w) 8501904 84580503 34731 120588 (C9C12C21) (47) 120588 (C9H2) (27) 120588 (C1H2) (15) ](C14C17) (5)

29 896 (w) 9017561 8963468 09206 120588 (C9C12C21) (73) 120588 (C21C24C27) (14)30 909 (w) 9065632 90105403 13451 120588 (C9C12C21) (46) 120588 (C9H2) (35) 120588 (C12C14C17) (9)31 933 (sh) 9170283 91129911 76343 120588 (O7C6O8) (86) 120588 (C9H2) (10)32 962 (m) 9470255 94064585 60649 120588 (C6O8C9) (99)33 mdash 9726775 96571834 70484 120588 (C6O8C9) (99)

34 984 (m) 10012212 99359199 344957 120596 (C1H2) (52) ] (C1C4) (15) 120575 (C4C6O8) (15) ] (C12C21)(15)

35 1015 (sh) 10171676 100915249 70006 ] (C12C21) (92)36 mdash 10219635 101383071 35045 ] (C21C24) (85) 120575 (C9C12O14) (9)37 1025 (sh) 10299052 102157589 185130 y (C1H2) (97)38 mdash 1040755 103215388 03554 ] (C21C24) (70) ] (C9C12) (14) y (C21H2) (5)39 mdash 10608287 105171458 55936 y (C21H2) (58) 120588 (C14C12H13) (29) 120588 (C14H2) (7)40 mdash 10640573 105485945 188097 ] (C21C24) (88) ] (C14C17) (8)41 1057 (m) 10767989 106726727 1926571 ] (C9O8) (82) ] (C14C17) (13)42 1060 (sh) 10895069 10796371 46500 120588 (C9H2) (40) 120575 (C9C12C21) (30) 120596 (C27H2) (25)43 1116 (w) 11506075 113903825 14631 120588 (C9C12H13) (51) 120575 (C9C12C21) (42)44 1191 11682621 115617915 32253 120588 (C14C12H13) (72) 120596 (C21H2) (16) 120588 (O8C9C12) (9)45 mdash 11850265 117244634 01695 120575 (C9C12C14) (94)

10 Organic Chemistry International

Table 3 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

46 mdash 1242923 122855525 17298 y (C21H2) (89)47 mdash 1258238 124337912 11546 120588 (C9C12C21) (35) 120596 (C21H2) (35) 120596 (C9H2) (27)48 mdash 12801017 126452842 779146 120596 (C21H2) (47) 120588 (C9C12C21) (37) 120588 (C9H2) (27)49 1272 1283202 126752616 3516365 120596 (C21H2) (60) y (C14H2) (27) y (C9H2) (10)50 mdash 12991286 128292094 44292 y (C9H2) (72) y (C21H2) (26)51 1295 13117811 129514505 72842 y (C14H2) (99)52 mdash 131875 130187577 68204 y (C14H2) (100)53 mdash 13264691 13093292 01479 y (C21H2) (97)54 mdash 13362199 131874163 04090 y (C24H2) (94) y (C21H2) (5)55 1340 1359997 134168063 10793 120596 (C21H2) (86) 120588 (C21C12C14) (7) 120596 (C9H2) (5)56 mdash 13800145 136097825 04801 120588 (C9C12C21) (43) 120575 (C9H12) (28) 120596 (C21H2) (25)

57 1357 13931134 137359902 28872 120596 (C9H2) (50) 120596 (C14H2) (23) 120575 (C21C12H13) (12) 120596(C21H2) (86)

58 mdash 14043849 138445461 09476 120596 (C21H2) (86) 120596 (C9H2) (12)59 mdash 14119509 139173911 08054 120596 (C9H2) (85) 120596 (C21H2) (14)60 1381 14145333 1394225 50233 120596 (C21H2) (54) 120596 (C9H2) (45)61 mdash 14173104 139689807 08100 120596 (C21H2) (89) 120596 (C9H2) (8)62 1408 14414398 142011302 305726 120596 (C9H2) (93) 120596 (C21H2) (5)

63 mdash 14831028 146015241 20326 120575 (C9H2) (38) 120575 (C21C12H13) (18) 120575 (C24C21C12) (15) 120575(C14H2) (13) 120575 (C24H2) (7) 120575 (C21H2) (6)

64 mdash 14876468 146451591 04300 120575 (C21C12H13) (33) 120575 (C27H2) (28) 120575 (C24H2) (20) 120575(C21H2) (10)

65 mdash 14916884 14683964 12432 120575 (C21H2) (54) 120575 (C9H2) (21) 120575 (C27H2) (11)

66 mdash 15000764 147644833 24692 120575 (C24H2) (32) 120575 (C21C12H13) (24) 120575 (C27H2) (8) 120575(C30H3) (8) 120575 (C21H2) (6)

67 mdash 1500718 147706413 70795 120575 (C30H3) (75) 120575 (C9H2) (11) 120575 (C27H2) (6)68 mdash 15025266 147879993 89950 120575 (C9H2) (74) 120575 (C17H3) (21)

69 1464 15081671 148421269 98400 120575 (C27H2) (26) 120575 (C30H3) (22) 120575 (C21H2) (14) 120575(C17H3) (14) 120575 (C24H2) (11)

70 mdash 15116225 148752807 105533 120575 (C21H2) (73) 120575 (C21C12H13) (6) 120575 (C24H2) (5) 120575(C17H3) (5)

71 mdash 1514069 14898752 56625 120575 (C24H2) (30) 120575 (C21H2) (29) 120575 (C21C24C27) (20) 120575(C27H2) (9)

72 1619 16787098 164738009 287096 ] (C1C4) (52) ] (C4C6) (22) 120575 (C9C12H13) (11) 120575(C21H2) (8)

73 1727 17668533 173134006 3155882 120575 (C9C12C21) (63) ] (C4C6) (16) 120575 (C21H2) (6) ](C6O7) (6)

74 mdash 2995932 287569419 20873 ] (C24H2) (35) ] (C14H2) (34) ] (C21H2) (25)

75 mdash 2998467 287800355 06759 ] (C24H2) (40) ] (C12H13) (29) ] (C21H2) (12) ](C14H2) (10)

76 mdash 3001649 288090203 135187 ] (C21H2) (92)77 mdash 30053152 288424116 132101 ] (C24H2) (87) ] (C24H2) (8)78 2861 3013385 289158948 585964 ] (C21H2) (45) ] (C30C32) (36) ] (C12H13) (12)79 2875 30178939 289569433 472871 ] (C30C32) (96)80 mdash 30236248 290091073 211397 ] (C14H12) (46) ] (C17H19) (32) ] (C17H18) (17)

81 mdash 30260401 290310887 159088 ] (C12H13) (30) ] (C17H19) (27) ] (C17H18) (13) ](C30C32) (12)

82 mdash 303455 291085214 329164 ] (C21H2) (66) ] (C14H2) (28)83 mdash 30404085 291618149 40314 ] (C21H2) (55) ] (C30H32) (27) ] (C12H13) (7)84 mdash 30437899 291925696 263738 ] (C21H2) (98)85 mdash 30609167 293482854 503404 ] (C21H2) (85) ] (C30C32) (12)86 2931 30786333 295092629 824131 ] (C30C32) (95)

Organic Chemistry International 11

Table 3 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

87 mdash 30833975 295525341 441245 ] (C30C32) (93)88 mdash 30842781 295605315 369537 ] (C17H19) (67) ] (C17H18) (18) ] (C21H2) (9)

89 mdash 30889498 296029541 151201 ] (C21H2) (52) ] (C9H2) (14) ] (C12H13) (14) ] (C14H2)(8) ] (C17H19) (7)

90 2961 30930704 296403663 595099 ] (C17H19) (36) ] (C14H2) (28) ] (C17H20) (10) ](C21H2) (10) ] (C17H18) (8) ] (C9H2) (6)

91 3038 31462567 301227655 52018 ] (C1C4) (50) ] (C1H2) (31) ] (C1H3) (10)92 3069 31857999 304808243 34136 ] (C4H5) (57) ] (C4C6) (23) ] (C1C4) (14)93 3104 3237707 309500628 44771 ] (C1H2) (70) ] (C1H3) (11) ] (C4H5) (7)aAssignments and potential energy distribution (PED) (contributing ge 5) for vibrational normal mode Types of vibration ] stretching 120575 deformation oout-of-plane bending 120596 wagging y twisting 120588 rocking 120591 torsion w weak m medium sh shoulderbNormal mode number

Abso

rban

ce

Wavenumbers (cmminus1)

121

08060402

01200 1300 1400 1500 1600 1700 1800

17721295

13401357

1381

14081464

1619 1637 1686

1727

(a)

IR in

tens

ity (k

mm

ol) 50

40

30

20

10

0

Wavenumbers (cmminus1)1200 1250 1300 1350 1400 1450 1500 1550 1600 1650 1700 1750 1800

1244 12841301

1311

1307

134113731390

1394

1417

14631476

14841491

1656

1735

(b)

IR in

tens

ity (k

mm

ol) 50

40

30

20

10

0

Wavenumbers (cmminus1)

1227

1264

12421284

1266

12941302

13411373 1393

1419

14601476

14871489

16461731

1200 1250 1300 1350 1400 1450 1500 1550 1600 1650 1700 1750 1800

(c)

Figure 3 Comparison of the experimental IR (a) C=O and C=C stretching and CH bending region (1800ndash1200 cmminus1) with the appropriatetheoretical B3LYP6-311+Glowastlowast spectra ((b) and (c)) for s-cis and s-trans 2-ethylhexyl acrylate respectively

are well correlated to the calculated peaks in DFT for bothconformers see Tables 2 and 3

The shoulders in the infrared spectrum at 1025 1015 cmminus1of weak to medium intensities may be correlated to the bands1037 1015 cmminus1 for s-cis and 1015 988 cmminus1 for the s-trans

conformer These bands are ascribed to the CH out-of-planebending modes of the vinyl group

The remaining bands of weak intensity in the experimen-tal IR spectrum are 909 896 and 852 cmminus1 These bandsare close to the ones at 911 996 and 847 cmminus1 for the s-cis

12 Organic Chemistry International

121

08060402

0700 800 900 1000 1100 1200

727 770

811

952 869909 933

962 9841015 1025

1057

11161060

1191

Abso

rban

ce

Wavenumbers (cmminus1)

(a)

20

10

0

728776 783

825

848895

900911 940 975

1000

10131037

1008 1152 11581180

1016

1139

1156

1191

700 800 900 1000 1100 1200Wavenumbers (cmminus1)

IR in

tens

ity (k

mm

ol)

(b)

725

775783

827

846 896

900

940 965

993

1009

10131021

1066

10331051

1054

1079 11381156

1171

700 800 900 1000 1100 1200Wavenumbers (cmminus1)

20

10

0IR in

tens

ity (k

mm

ol)

(c)

Figure 4 Comparison of the experimental IR (a) CO stretching and CH bending region (1200ndash700 cmminus1) with the appropriate theoreticalB3LYP6-311+Glowastlowast spectra ((b) and (c)) for s-cis and s-trans 2-ethylhexyl acrylate respectively

conformation of the titlemolecule All the vibrational normalmodes in this region are not pure and the majority of themwere ascribed according to PED calculations to CH bending(for more details see Tables 2 and 3)

54 Region below 700 cmminus1 This spectral region includesthe bands associated with C=CndashC CndashOndashC O=CndashO OndashCndashC CndashCndashC and CndashCndashC bending and torsion modes aboutthe single bonds OndashC and CndashC The frequencies and PEDcalculations are presented in Tables 2 and 3 Comparing the23 first normal modes for the two conformers we notice thatthey have the same type of vibrational modes However thenormal modes 16 17 and 18 represent CCC bending in the s-trans andCHandCCC rockingmodes in the s-cis conformer

Due to the lack of experimental data on this region wecompare our calculated frequencies to some experimental IRbands of related molecules presented in the literature Thebands at 356 254 116 and 100 cmminus1 are close to the bandsat 349(A1015840) 244(A10158401015840) 114(A10158401015840) and 114 cmminus1 (A10158401015840) reported byDulce et al [28] From the same work the bands at 530 244114 and 114 cmminus1 belonging to A10158401015840 symmetry for the s-trans

methyl acrylate in liquid state are close to our calculatedbands in DFT at 542 244 116 and 106 cmminus1

6 Conclusions

Themid-IR spectrum of 2-ethylhexyl acrylate was measuredand interpreted with support of the DFTB3LYP6-311+Glowastlowastcalculated vibrational spectra followed by potential energydistribution analysis Assuming the s-cis and s-trans confor-mations we found two stable conformations close in theirenergies The fully optimized geometries of s-cis and s-transconformations by DFTB3LYP6-311+Glowastlowast were comparedwith the experimental and theoretical data presented in theliterature on the methyl acrylate molecule The compari-son shows a good agreement The experimental vibrationalspectrum is in good agreement with the theoretical spectracalculated for the two conformations Two neighbor bandsin the IR spectrum at 1619 and 1637 cmminus1 may be used ascharacteristic bands to locate and distinguish the existence ofone or both conformations

Organic Chemistry International 13

References

[1] M Salkind E H Riddle and R W Keefer ldquoAcrylates andmethacrylates ester manufacture and marketsrdquo Industrial ampEngineering Chemistry Research vol 51 no 11 pp 1328ndash13341959

[2] K S Anseth S M Newman and C N Bowman ldquoPolymericdental composites properties and reaction behavior of multi-methacrylate dental restorationsrdquo Advances in Polymer Sciencevol 122 pp 176ndash217 1995

[3] J G Kloosterboer ldquoNetwork formation by chain crosslink-ing photopolymerization and its application in electronicsrdquoAdvances in Polymer Science vol 84 pp 1ndash61 1988

[4] K Matyjaszewski Y Gnanou and L Leibler MacromolecularEngineering vol 1 Wiley-VCH Weinheim Germany 2007

[5] M Orgill B L Baker and N L Owen ldquoFTIR studies ofconformational isomerism in acrylates and acrylic acidsrdquo Spec-trochimica Acta A vol 55 no 5 pp 1021ndash1024 1999

[6] M Salkind ldquoReaches into the marketrdquo Industrial amp EngineeringChemistry Research vol 56 pp 62ndash110 1964

[7] E Takacs K Dajka and L Wojnarovits ldquoStudy of high-energyradiation initiated polymerization of butyl acrylaterdquo RadiationPhysics and Chemistry vol 63 no 1 pp 41ndash44 2002

[8] H Yu J Peng M Zhai J Li G Wei and J Qiao ldquoRadiation-induced copolymerization of styrenen-butyl acrylate in thepresence of ultra-fine powdered styrene-butadiene rubberrdquoRadiation Physics and Chemistry vol 76 no 11-12 pp 1736ndash1740 2007

[9] P F Canamero J Luis de la Fuente and M Fermandez-GarcıaldquoCuring kinetic study using a well-controlled multifunctionalcopolymer based on glycidyl methacrylaterdquo European PolymerJournal vol 45 no 9 pp 2665ndash2673 2009

[10] DMathew C P ReghunadhanNair and K N Ninan ldquoPendantcyanate functional vinyl polymers and imidophenolic-triazinesthereof synthesis and thermal propertiesrdquo European PolymerJournal vol 36 no 6 pp 1195ndash1208 2000

[11] S Mitra S Chattopadhyay S Sabharwal and A K BhowmickldquoElectron beam crosslinked gels-Preparation characterizationand their effect on the mechanical dynamic mechanical andrheological properties of rubbersrdquoRadiation Physics and Chem-istry vol 79 no 2 pp 289ndash296 2010

[12] P Canamero-Martınez M Fermandez-Garcıa and J Luis de laFuente ldquoRheological cure characterization of a polyfunctionalepoxy acrylic resinrdquo Reactive and Functional Polymers vol 70no 10 pp 761ndash766 2010

[13] F Chu T McKenna and S Lu ldquoCuring kinetics of an acrylicresinepoxy resin system using dynamic scanning calorimetryrdquoEuropean Polymer Journal vol 33 no 6 pp 837ndash840 1997

[14] M C Douskey M S Gebhard A V McCormick et alldquoSpectroscopic studies of a novel cyclic oligomer with pendantalkoxysilane groupsrdquo Progress in Organic Coatings vol 45 no2-3 pp 145ndash157 2002

[15] R J Day P A Lovell and A A Wazzan ldquoToughened car-bonepoxy composites made by using coreshell particlesrdquoComposites Science andTechnology vol 61 no 1 pp 41ndash56 2001

[16] K Bolton D G Lister and J Sheridan ldquoRotational isomerismbarrier to internal rotation and electric dipole moment ofacrylic acid bymicrowave spectroscopyrdquo Journal of the ChemicalSociety Faraday Transactions 2 vol 70 pp 113ndash123 1974

[17] S W Charles F C Cullen N L Owen and G A WilliamsldquoInfrared spectrum and rotational isomerism of acrylic acidrdquoJournal of Molecular Structure vol 157 no 1ndash3 pp 17ndash25 1987

[18] K Bolton N L Owen and J Sheridan ldquoMicrowave spectra ofrotational isomers of acrylic acidrdquoNature vol 218 no 5138 pp266ndash267 1968

[19] G Williams N L Owen and J Sheridan ldquoSpectroscopicstudies of some substitutedmethyl formatesmdashpart 1microwavespectra and internal rotation barriers of methyl-fluoroformate-propiolate -cyanoformate -acrylate and -acetaterdquo Transac-tions of the Faraday Society vol 67 pp 922ndash949 1971

[20] T Tsuji H Ito H Takeuchi and S Konaka ldquoMolecularstructure and conformation ofmethylmethacrylate determinedby gas electron diffractionrdquo Journal of Molecular Structure vol475 no 1 pp 55ndash63 1999

[21] T Egawa S Maekawa H Fujiwara Takeuchi H Takeuchi andS Konaka ldquoMolecular structure and conformation of methylacrylate a gas electron diffraction study augmented by ab initiocalculation and rotational constantsrdquo Molecular Structure andSpectroscopy vol 352 pp 193ndash201 1995

[22] A Virdi V P Gupta and A Sharma ldquoAb initio studies onconformation vibrational and electronic spectra of methylmethacrylaterdquo Journal ofMolecular Structure vol 634 no 5 pp53ndash65 2003

[23] B L Baker M Orgill N L Owen et al ldquoThe molecularconformation of methyl methacrylatemdashan infrared and abinitio studyrdquo Journal of Molecular Structure vol 356 no 2 pp95ndash104 1995

[24] A N Mitra and I Santhanan ldquoRelativistic qqq spectra fromBethe-Salpeter premisesrdquo Physics Letters B vol 104 no 1 pp62ndash66 1981

[25] K Fan and J E Boggs ldquoRotational isomerism of acrylic acidrdquoJournal of Molecular Structure vol 157 no 1ndash3 pp 31ndash41 1987

[26] P Carmona and J Moreno ldquoThe infrared spectra and structureof methyl acrylaterdquo Journal of Molecular Structure vol 82 no3-4 pp 177ndash185 1982

[27] R J Loncharich T R Schwartz and K N Houk ldquoTheoreticalstudies of conformations of acrolein acrylic acid methyl acry-late and their Lewis acid complexesrdquo Journal of the AmericanChemical Society vol 109 no 1 pp 14ndash23 1987

[28] M Dulce G Faria J J C Teixeira-Dias and R FaustoldquoVibrational spectra and structure of methyl trans-crotonaterdquoVibrational Spectroscopy vol 2 no 2-3 pp 43ndash60 1991

[29] J J C Teixeira-Dias and R Fausto ldquoMolecular structure ofmethyl acrylate the high energy s-trans-(CO) conformerrdquoJournal of Molecular Structure vol 282 no 1-2 pp 123ndash1291993

[30] A J Bowles W O George and D B Cunliffe-Jones ldquoConfor-mations of some120572120573-unsaturated carbonyl compoundsmdashpart IIinfrared and Raman spectra of methyl and ethyl acrylates andtranscrotonatesrdquo Journal of the Chemical Society B pp 1070ndash1075 1970

[31] A D Becke ldquoDensity-functional thermochemistry IIIThe roleof exact exchangerdquoThe Journal of Chemical Physics vol 98 no7 pp 5648ndash5652 1993

[32] C Lee W Yang and R G Parr ldquoDevelopment of the Colle-Salvetti correlation-energy formula into a functional of theelectron densityrdquo Physical Review B vol 37 no 2 pp 785ndash7891988

[33] H Yoshida K Takeda J Okamura A Ehara and H MatsuuraldquoA new approach to vibrational analysis of large molecules bydensity functional theory wavenumber-linear scalingmethodrdquoJournal of Physical Chemistry A vol 106 no 14 pp 3580ndash35862002

14 Organic Chemistry International

[34] H Yoshida A Ehara and H Matsuura ldquoDensity functionalvibrational analysis using wavenumber-linear scale factorsrdquoChemical Physics Letters vol 325 no 4 pp 477ndash483 2000

[35] M J Frisch G W Trucks H B Schlegel et al Gaussian 03Revision B 01 Gaussian Pittsburgh Pa USA 2003

[36] J M L Martin and C Van Alsenoy GAR2PED A Program toObtain a Potential Energy Distribution from a Gaussian ArchiveRecord University of Antwerp 2009

[37] P Pulay G Fogarasi F Pang and J E Boggs ldquoSystematicab initio gradient calculation of molecular geometries forceconstants and dipole moment derivativesrdquo Journal of theAmerican Chemical Society vol 101 no 10 pp 2550ndash2560 1979

[38] S Mishra D Chaturvedi N Kumar P Tandon and H WSiesler ldquoAn ab initio and DFT study of structure and vibrationalspectra of 120574 form of Oleic acid comparison to experimentaldatardquo Chemistry and Physics of Lipids vol 163 no 2 pp 207ndash217 2010

[39] W O George D V Hassid and W F Maddams ldquoConfor-mations of some 120572120573-unsaturated carbonyl compoundsmdashpartIII infrared solution spectra of methyl [2H3]methyl ethyland [2H5]ethyl acrylates and trans-crotonatesrdquo Journal of theChemical Society Perkin Transactions 2 no 4 pp 400ndash4041972

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

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Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Medicinal ChemistryInternational Journal of

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Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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CatalystsJournal of

Page 6: Research Article Molecular Structure and Vibrational Spectra ...e molecular geometry, vibrational frequencies, and infrared intensities have been calculated by using density functional

6 Organic Chemistry International

Table 2 Frequencies and PEDs of s-cis 2-ethylhexyl acrylate

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

1 mdash 305017 307519 01860 120591 (O8C9) (63) 120591 (C9C12) (35)2 mdash 367273 3702484 19384 120591 (C9C12) (83) 120591 (O8C9) (17)3 mdash 482766 4865862 12435 120591 (C9C12) (98)

4 mdash 747391 7529828 00096 120588 (C30H3) (62) 120591 (C9C12) (17) 120591 (O8C9) (7) 120588 (C14H2)(7)

5 mdash 931493 9381827 07602 120591 (C9C12) (84) 120588 (C14H2) (15)6 mdash 996177 10032262 06102 120591 (C9C12) (76) 120591 (C9C12) (21)7 mdash 1159962 11678605 02949 120591 (C9C12) (94)8 mdash 1338201 13469244 07707 120591 (C9C12) (43) 120588 (C27H3) (31) 120588 (C9H2) (15)9 mdash 1461924 14711591 00469 120591 (C9C12) (58) 120588 (C9H2) (17) 120588 (C14H2) (16)10 mdash 2010708 20216112 18808 120591 (C9C12) (89) 120575 (C6O8C9) (5)11 mdash 2139423 21505753 27336 120591 (C9C12) (98)12 mdash 2341345 23527792 06986 120588 (C30H3) (94)13 mdash 2537618 25491989 12866 120588 (C30H3) (99)14 mdash 2654468 26660766 07334 120591 (C9C12) (83) 120588 (C30H3) (14)15 mdash 2851163 28627176 35548 120588 (C30H3) (78) 120591 (C9C12) (18)16 mdash 3157568 31687874 05814 120588 (C9H2) (89) 120588 (C17H3) (6)17 mdash 3551126 35614657 02263 120588 (C17H3) (36) 120588 (C9C12C14) (31) 120588 (C9H2) (19)

18 mdash 3759666 37693349 43994 120588 (C24C27C30) (27) 120588 (C9C12C14) (23) 120588 (C17H3) (17) 120575(C21C24C27) (10) 120588 (C9C12H13) (10) 120575 (C21H2) (8)

19 mdash 470318 47080422 06863 120588 (C9C12C21) (72) 120588 (C17H3) (11) 120588 (C9H2) (5)20 mdash 5120856 51226637 62054 120588 (C9C12C14) (80) 120588 (C9H2) (7) 120575 (C21C12C14) (6)21 mdash 5273488 52740376 01504 120588 (C9H2) (87) O (C6O7) (9)22 mdash 5339978 53399558 11100 120588 (C9C12C14) (77) 120588 (C6O8C9) (8)23 mdash 681189 67955184 31928 120588 (C9C12C14) (42) 120575 (O7C6C4) (42) 120588 (C6O8C9) (5)24 731 (m) 7312122 7288586 45137 120588 (C21C24C27) (99)25 748 (sh) 7795982 776474 10039 120588 (C27H2) (65) 120588 (C9C12C14) (18) 120588 (C14H2) (12)

26 770 (m) 7863101 78307298 16507 120588 (C27H2) (36) 120588 (C21H2) (32) 120588 (C14H2) (23) 120588(C17H3) (8)

27 811 (m) 8295925 82559191 249487 120588 (C9H2) (73) O (C6O7) (21) y (C1H2) (8)28 852 (w) 8523514 84792486 30736 120588 (C9C12C21) (82) 120588 (C9H2) (16)

29 896 (w) 9016472 89624016 10870 120588 (C9C12H21) (62) 120596 (C24H2) (16) y (C21H2) (9) 120575(C30H3) (8)

30 mdash 9068585 90134317 10553 120588 (C9C12H21) (86) 120588 (C9H2) (10)31 909 (w) 9172167 91148352 72928 120588 (C9H2) (58) 120596 (C27H2) (27) 120588 (O7C6O8) (12)32 933 (sh) 9478927 94149381 59570 120575 (C14C12H3) (50) 120596 (C27H2) (46)

33 962 (m) 9836705 97645643 251442 120588 (C9C12H13) (83) 120575 (C6O8C9) (21) y (C21H2) (14) y(C27H2) (11) y (C14H2) (11)

34 984 (m) 10069955 99922751 255334 120596 (C1H2) (84) y (C14H2) (10)

35 mdash 10169241 100891495 51103 120588 (C14H2) (41) 120588 (C9C12C21) (24) 120575 (C12C21C24) (23) 120588(C17H3) (7)

36 1015 (sh) 10232765 101511136 260306 o (C4H5) (99)37 mdash 10258451 101761651 19504 120575 (C9C12C14) (98) ] (C9O8) (5)38 1025 (sh) 10459956 103726182 278636 y (C24H2) (42) ] (C9C12) (42) ] (O8C9) (6)39 mdash 10621068 105295957 04109 120588 (C14C12H13) (83) ] (C27C30) (12)40 mdash 10659864 105673835 04863 ] (C14C17) (83) ] (C24C27) (11)41 mdash 10835238 107381387 16531 120596 (C9H2) (83) 120596 (C21H2) (15)42 1057 (m) 10894787 107960965 22238 120588 (C9H2) (84) 120596 (C27H2) (14)

Organic Chemistry International 7

Table 2 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

43 mdash 11505508 113898319 19252 120588 (C9C12H13) (96)

44 1116 (w) 11685589 115646723 118316 120575 (C12C21C24) (67) 120588 (C14C12H13) (9) 120588 (O8C9C12) (7)120575 (C14C12C21) (67)

45 1060 (sh) 11856606 117306145 00857 120575 (C9C12C14) (63) 120588 (C30H3) (26) 120575 (C12C14C17) (6)46 1191 12051044 11919167 6261232 120588 (C6C4H5) (87)47 mdash 12437853 12293901 03621 y (C21H2) (94) y (C27H2) (5)48 mdash 12586429 124377093 10505 120588 (C9H2) (76) 120596 (C21H2) (23)49 mdash 12817118 12660853 07178 y (C14H2) (55) 120596 (C21H2) (44)50 mdash 13003301 128408198 13337 120596 (C21H2) (93)

51 mdash 13179028 130105761 111581 120596 (C24H2) (24) 120588 (C9C12H13) (17) y (C14H2) (13) 120596(C27H2) (7) 120588 (C6O8C9) (5)

52 1272 13245992 130752384 683227 y (C27H2) (37) 120588 (C9C12H13) (29) y (C21H2) (22) y(C14H2) (6)

53 1295 13282386 131103753 60034 y (C27H2) (93)54 mdash 13381682 132062195 05711 y (C24H2) (70) y (C27H2) (28)55 1340 13610156 134266291 13124 120596 (C21H2) (78) 120596 (C9H2) (21)56 mdash 13812224 13621423 04732 120588 (C9C12C21) (78) 120596 (C21H2) (21)57 1357 13942309 137467547 33349 120596 (C9H2) (95)58 mdash 14045719 138463467 45032 120596 (C24H2) (95) 120596 (C21H2) (5)59 1381 14109338 139075996 73272 120596 (C21H2) (97)60 mdash 14141585 139386422 23703 120596 (C21H2) (99)61 mdash 14180649 139762426 04645 120596 (C21H2) (93) 120596 (C14H2) (6)62 1408 1437761 141657487 831633 120596 (C9H2) (49) 120596 (C21H2) (26) 120575 (CH2) (20)

63 mdash 14861635 146309161 10310 120575 (C21H2) (40) 120575 (C24H2) (20) 120575 (C12C21C24) (12) 120575(C14H2) (7)

64 mdash 14883957 1465235 10310 120575 (C27H2) (29) 120575 (C21H2) (28) 120575 (C24H2) (18) 120575(C12C21C24) (14) 120575 (C14H2) (10) 120575 (C27H2) (10)

65 mdash 1492293 146897685 13617 120575 (C21H2) (67) 120575 (C27H2) (11) 120575 (C14H2) (7)66 mdash 14999113 147628987 83925 120575 (C30H3) (88) 120575 (C27H2) (10)

67 mdash 15017672 147807111 43738 120575 (C21H2) (29) 120575 (C30H3) (28) 120575 (C24H2) (15) 120575(C21C12H13) (11) 120575 (C14H2) (6)

68 mdash 1503707 147993276 35078 120575 (C27H2) (31) 120575 (C21H2) (29) 120575 (C9H2) (18)

69 1464 15093473 148534511 99123 120575 (C17H3) (27) 120575 (C27H2) (26) 120575 (C21H2) (10) 120575(C12C21C24) (8) 120575 (C24H2) (7) 120575 (C12C14C21) (6)

70 mdash 15106836 148662726 108575 120575 (C21H2) (83) 120575 (C27H2) (10)

71 mdash 15154657 149121508 60184 120575 (C24H2) (42) 120575 (C21C24C27) (25) 120575 (C27H2) (13) 120575(C21H2) (10)

72 1637 16875503 165581242 269151 ] (C1C4) (87) 120575 (C1H2) (7)

73 1727 1770955 173524092 2434946 ] (C6O7) (80) 120575 (O8C9H12) (7) 120575 (C21H2) (5) ] (C4C6)(5)

74 mdash 29973914 287702371 27860 ] (C21H22) (45) ] (C14H2) (33) ] (C12H13) (14)75 mdash 29998142 287923075 17988 ] (C21H2) (76) ] (C24H2) (14)

76 mdash 30020159 288123622 138469 ] (C27H2) (33) ] (C24H2) (32) ] (C30H31) (22) ](C21H2) (6)

77 mdash 30058916 288476609 146381 ] (C21H2) (74) ] (C14H2) (14) ] (C12H13) (5)78 2861 30145745 289267245 457319 ] (C12H13) (63) ] (C30H31) (31)79 2875 30180275 289581595 559324 ] (C30H31) (98)80 mdash 30238407 290110723 222942 ] (C17H19) (58) ] (C17H18) (29)

81 mdash 30261436 290320306 164278 ] (C17H19) (32) ] (C14H2) (29) ] (C17H18) (15) ](C30C31) (8) ] (C21H2) (6)

82 mdash 30348324 291110906 351134 ] (C14H2) (96)

8 Organic Chemistry International

Table 2 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

83 mdash 30419158 291755246 160910 ] (C27H2) (38) ] (C9H2) (20) ] (C14H2) (19) ] (C21H2)(6) ] (C24H) (6)

84 mdash 30431697 29186929 145616 ] (C27H2) (47) ] (C9H2) (26) ] (C24H2) (10) ] (C14H2)(7)

85 mdash 3062906 293663657 465673 ] (C21H2) (55) ] (C27H2) (25) ] (C24H2) (9) ] (C12H13)(5)

86 2931 30788255 295110087 858987 ] (C27H2) (62) ] (C27H30) (10) ] 295503236 (C30H3)(9) ] (C9H2) (6) ] (C17H19) (6)

87 mdash 30831541 295503236 455349 ] (C30H31) (99)

88 mdash 30845244 295627682 351235 ] (C17H19) (67) ] (C17C19) (67) ] (C17C18) (17) ](C30H31) (15)

89 mdash 30879105 29593517 195239 ] (C9H2) (63) ] (O8C9) (16) ]-(C12H13) (11) ] (C17C19)(6)

90 2961 30931423 296410191 561433 ] (C17H19) (38) ] (C9H2) (26) ] (C17H20) (12) ](C14H2) (10) ] (C17H18) (9)

91 3038 31428663 300920422 51952 ] (C1C4) (45) ] (C1H2) (38) ] (C1H3) (9)92 mdash 3185092 304744188 32650 ] (C1H2) (95)93 3104 32359105 309338372 23617 ] (C4H5) (67) ] (C1H2) (22) ] (C1H3) (6)aAssignments and potential energy distribution (PED) (contributing ge 5) for vibrational normal mode Types of vibration ] stretching 120575 deformation oout-of-plane bending 120596 wagging y twisting 120588 rocking 120591 torsion w weak m medium sh shoulderbNormal mode number

1655 cmminus1 for s-cis conformer (Figure 3(b)) and 1647 cmminus1 forthe s-trans conformer (Figure 3(c)) The band at 1637 cmminus1may be used to definitely indicate that conformer with s-transarrangement of acrylic moiety is present or not in the liquid2-ethylhexyl acrylate

In the region from 1500 to 1200 cmminus1 in the experimen-tal spectrum (Figure 3) there are four bands of mediumintensity located at 1464 1408 1295 and 1272 cmminus1 Thebands of weak intensity of account of three are locatedat 1381 1357 and 1340 cmminus1 The calculated frequencies inthis region for the s-cis and s-trans conformations haveclose energies for each normal mode and the differencesdo not exceed 5 cmminus1 Based on the assignments reportedby Dulce et al [28] and our PED calculations we haveascribed the theoretical frequencies 1485 cmminus1 (s-cis) and1484 cmminus1 (s-trans) to the experimental band at 1464 cmminus1and they are representing a C

17H3symmetric bending The

calculated frequencies at 1479 1478 and 1476 cmminus1 may becontributed to the experimental band at 1464 cmminus1 due toits relatively large middle width of about 75 cmminus1 Mishra etal [38] have reported the experimental and the theoreticalIR spectra of 120574 form of oleic acid many peaks reported inthe region 1370 to 1220 cmminus1 for the CH

2carboxyl-sided

chain correspond approximately to those we found in ourspectrum from 1400 to 1200 cmminus1 and all of them may beassigned to CH

2deformation The assignment is based on

the bands intensities we found a good correlation betweenthe experimental and the theoretical spectra One shouldpoint out that the very intense bands predicted at 1267 and

1264 cmminus1 for s-trans form reproduce well the asymmetricshape of the experimental band at 1272 cmminus1 For bandsassignment see Tables 2 and 3

53 The CO Stretching and CH Bending Vibrations (1200ndash700 cmminus1 Figure 4) In this region in the IR spectrum thereis one very strong band at 1192 cmminus1 with weak shoulder at1160 cmminus1 and four medium intensity bands 1057 984 962shoulder at 933 and 811 cmminus1 The bands at 1116 1025 909896 852 770 and 727 cmminus1 (shoulder at 748 cmminus1) are ofweak intensity (Figure 4) Based on PEDs and intensities ofthe calculated frequencies we correlate the two intense bandsat 1192 and 1156 cmminus1 for the more stable and the less stableconformers to the band at 1191 cmminus1 in the experimentalIR spectrum The medium bands in IR spectrum are wellreproduced by the calculated peaks at 1079 999 976 941 and811 cmminus1 for the s-cis conformer and 1067 993 940 911 and828 cmminus1 for the s-trans conformer They may be ascribed toCH2rocking C

1H2wagging CCH rocking O

8C9 and C

1H2

twisting The peaks predicted by DFT at 728 and 783 cmminus1 ins-cis form and the peaks at 726 and 782 cmminus1 in the s-transformmay be correlated to the bands at 727 and 770 cmminus1 andthey are assigned to the CH

2deformations of the alkyl sides

of the title moleculeIn the IR spectra of 2-ethylhexyl acrylate reported in

this work there are a few bands with weak to very weakintensity which do not appear in the IR spectra of methylacrylate reported by Dulce et al [28] and George et al [39]These bands appear at 1157 1120 1052 and 1022 cmminus1 and they

Organic Chemistry International 9

Table 3 Frequencies and PEDs of s-trans 2-ethylhexyl acrylate

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

1 mdash 295569 2979981 13888 120591 (C21C24) (95)2 mdash 312922 3154848 12915 120591 (C21C24) (100)3 mdash 453002 4566086 00227 120591 (C21C24) (91) 120591 (O8C9) (6)4 mdash 69075 6959818 00113 120591 (C21C24) (98)5 mdash 916561 9231657 07304 120588 (C14H2) (64) 120591 (C9C12) (19) 120591 (C24C21) (15)6 mdash 106795 10753821 00788 120591 (C12C14) (92)7 mdash 116406 11719786 04606 120591 (O8C9) (90) 120591 (C21C24) (7)8 mdash 128002 12884855 07652 120591 (C21C24) (99)9 mdash 1377311 13862015 00737 120591 (C24C21) (94)10 mdash 1886176 18967867 24795 120591 (C24C21) (53) O (O8C9) (44)11 mdash 1964898 19756995 22280 120588 (C9H2) (82) 120591 (C9C12) (13)12 mdash 2346 23574391 17535 120588 (C30H3) (90) 120591 (C21C24) (7)13 mdash 2495865 25074252 32507 120588 (C30H3) (78) 120591 (C12C21) (19)14 mdash 2623636 26352416 12259 120588 (C9H2) (72) 120588 (C17H3) (22)15 mdash 2741636 27532362 05126 120591 (C12C21) (96)16 mdash 3352283 33631302 04554 120575 (C21C12C14) (93)17 mdash 3546136 355649 01655 120575 (C21C12C24) (95)18 mdash 406411 40725451 25402 120575 (C9C12C14) (92)19 mdash 4713032 47178287 10320 120588 (C9C12C14) (70) 120575 (C9C12C21) (12) 120588 (C14H2) (11)20 mdash 5098943 51009251 04733 y (C1H2) (86) O (C6O8) (12)

21 mdash 5140157 51418098 73067 120588 (C12C14C17) (38) 120588 (C9C12C21) (15) 120588 (C12C21) (14)120588 (C14C12H13) (13) 120588 (C1H2) (8) 120575 (C12C21C24) (7)

22 mdash 550859 55070531 22808 120588 (C9C12C14) (78) 120588 (C6O8C9) (9) 120588 (C1H2) (6)23 mdash 6360175 6349572 19146 120588 (O8C9C12) (97)24 727 (m) 7284338 72612214 43677 120588 (C9C12C21) (92)25 mdash 778027 77492902 06843 120588 (C9C12C21) (98)26 770 (m) 785397 78217532 18732 120588 (C21H2) (59) 120588 (C14H2) (36)27 811 (m) 8321364 82808904 215147 y (C1H2) (94) 120588 (C9H2) (5)

28 852 (w) 8501904 84580503 34731 120588 (C9C12C21) (47) 120588 (C9H2) (27) 120588 (C1H2) (15) ](C14C17) (5)

29 896 (w) 9017561 8963468 09206 120588 (C9C12C21) (73) 120588 (C21C24C27) (14)30 909 (w) 9065632 90105403 13451 120588 (C9C12C21) (46) 120588 (C9H2) (35) 120588 (C12C14C17) (9)31 933 (sh) 9170283 91129911 76343 120588 (O7C6O8) (86) 120588 (C9H2) (10)32 962 (m) 9470255 94064585 60649 120588 (C6O8C9) (99)33 mdash 9726775 96571834 70484 120588 (C6O8C9) (99)

34 984 (m) 10012212 99359199 344957 120596 (C1H2) (52) ] (C1C4) (15) 120575 (C4C6O8) (15) ] (C12C21)(15)

35 1015 (sh) 10171676 100915249 70006 ] (C12C21) (92)36 mdash 10219635 101383071 35045 ] (C21C24) (85) 120575 (C9C12O14) (9)37 1025 (sh) 10299052 102157589 185130 y (C1H2) (97)38 mdash 1040755 103215388 03554 ] (C21C24) (70) ] (C9C12) (14) y (C21H2) (5)39 mdash 10608287 105171458 55936 y (C21H2) (58) 120588 (C14C12H13) (29) 120588 (C14H2) (7)40 mdash 10640573 105485945 188097 ] (C21C24) (88) ] (C14C17) (8)41 1057 (m) 10767989 106726727 1926571 ] (C9O8) (82) ] (C14C17) (13)42 1060 (sh) 10895069 10796371 46500 120588 (C9H2) (40) 120575 (C9C12C21) (30) 120596 (C27H2) (25)43 1116 (w) 11506075 113903825 14631 120588 (C9C12H13) (51) 120575 (C9C12C21) (42)44 1191 11682621 115617915 32253 120588 (C14C12H13) (72) 120596 (C21H2) (16) 120588 (O8C9C12) (9)45 mdash 11850265 117244634 01695 120575 (C9C12C14) (94)

10 Organic Chemistry International

Table 3 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

46 mdash 1242923 122855525 17298 y (C21H2) (89)47 mdash 1258238 124337912 11546 120588 (C9C12C21) (35) 120596 (C21H2) (35) 120596 (C9H2) (27)48 mdash 12801017 126452842 779146 120596 (C21H2) (47) 120588 (C9C12C21) (37) 120588 (C9H2) (27)49 1272 1283202 126752616 3516365 120596 (C21H2) (60) y (C14H2) (27) y (C9H2) (10)50 mdash 12991286 128292094 44292 y (C9H2) (72) y (C21H2) (26)51 1295 13117811 129514505 72842 y (C14H2) (99)52 mdash 131875 130187577 68204 y (C14H2) (100)53 mdash 13264691 13093292 01479 y (C21H2) (97)54 mdash 13362199 131874163 04090 y (C24H2) (94) y (C21H2) (5)55 1340 1359997 134168063 10793 120596 (C21H2) (86) 120588 (C21C12C14) (7) 120596 (C9H2) (5)56 mdash 13800145 136097825 04801 120588 (C9C12C21) (43) 120575 (C9H12) (28) 120596 (C21H2) (25)

57 1357 13931134 137359902 28872 120596 (C9H2) (50) 120596 (C14H2) (23) 120575 (C21C12H13) (12) 120596(C21H2) (86)

58 mdash 14043849 138445461 09476 120596 (C21H2) (86) 120596 (C9H2) (12)59 mdash 14119509 139173911 08054 120596 (C9H2) (85) 120596 (C21H2) (14)60 1381 14145333 1394225 50233 120596 (C21H2) (54) 120596 (C9H2) (45)61 mdash 14173104 139689807 08100 120596 (C21H2) (89) 120596 (C9H2) (8)62 1408 14414398 142011302 305726 120596 (C9H2) (93) 120596 (C21H2) (5)

63 mdash 14831028 146015241 20326 120575 (C9H2) (38) 120575 (C21C12H13) (18) 120575 (C24C21C12) (15) 120575(C14H2) (13) 120575 (C24H2) (7) 120575 (C21H2) (6)

64 mdash 14876468 146451591 04300 120575 (C21C12H13) (33) 120575 (C27H2) (28) 120575 (C24H2) (20) 120575(C21H2) (10)

65 mdash 14916884 14683964 12432 120575 (C21H2) (54) 120575 (C9H2) (21) 120575 (C27H2) (11)

66 mdash 15000764 147644833 24692 120575 (C24H2) (32) 120575 (C21C12H13) (24) 120575 (C27H2) (8) 120575(C30H3) (8) 120575 (C21H2) (6)

67 mdash 1500718 147706413 70795 120575 (C30H3) (75) 120575 (C9H2) (11) 120575 (C27H2) (6)68 mdash 15025266 147879993 89950 120575 (C9H2) (74) 120575 (C17H3) (21)

69 1464 15081671 148421269 98400 120575 (C27H2) (26) 120575 (C30H3) (22) 120575 (C21H2) (14) 120575(C17H3) (14) 120575 (C24H2) (11)

70 mdash 15116225 148752807 105533 120575 (C21H2) (73) 120575 (C21C12H13) (6) 120575 (C24H2) (5) 120575(C17H3) (5)

71 mdash 1514069 14898752 56625 120575 (C24H2) (30) 120575 (C21H2) (29) 120575 (C21C24C27) (20) 120575(C27H2) (9)

72 1619 16787098 164738009 287096 ] (C1C4) (52) ] (C4C6) (22) 120575 (C9C12H13) (11) 120575(C21H2) (8)

73 1727 17668533 173134006 3155882 120575 (C9C12C21) (63) ] (C4C6) (16) 120575 (C21H2) (6) ](C6O7) (6)

74 mdash 2995932 287569419 20873 ] (C24H2) (35) ] (C14H2) (34) ] (C21H2) (25)

75 mdash 2998467 287800355 06759 ] (C24H2) (40) ] (C12H13) (29) ] (C21H2) (12) ](C14H2) (10)

76 mdash 3001649 288090203 135187 ] (C21H2) (92)77 mdash 30053152 288424116 132101 ] (C24H2) (87) ] (C24H2) (8)78 2861 3013385 289158948 585964 ] (C21H2) (45) ] (C30C32) (36) ] (C12H13) (12)79 2875 30178939 289569433 472871 ] (C30C32) (96)80 mdash 30236248 290091073 211397 ] (C14H12) (46) ] (C17H19) (32) ] (C17H18) (17)

81 mdash 30260401 290310887 159088 ] (C12H13) (30) ] (C17H19) (27) ] (C17H18) (13) ](C30C32) (12)

82 mdash 303455 291085214 329164 ] (C21H2) (66) ] (C14H2) (28)83 mdash 30404085 291618149 40314 ] (C21H2) (55) ] (C30H32) (27) ] (C12H13) (7)84 mdash 30437899 291925696 263738 ] (C21H2) (98)85 mdash 30609167 293482854 503404 ] (C21H2) (85) ] (C30C32) (12)86 2931 30786333 295092629 824131 ] (C30C32) (95)

Organic Chemistry International 11

Table 3 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

87 mdash 30833975 295525341 441245 ] (C30C32) (93)88 mdash 30842781 295605315 369537 ] (C17H19) (67) ] (C17H18) (18) ] (C21H2) (9)

89 mdash 30889498 296029541 151201 ] (C21H2) (52) ] (C9H2) (14) ] (C12H13) (14) ] (C14H2)(8) ] (C17H19) (7)

90 2961 30930704 296403663 595099 ] (C17H19) (36) ] (C14H2) (28) ] (C17H20) (10) ](C21H2) (10) ] (C17H18) (8) ] (C9H2) (6)

91 3038 31462567 301227655 52018 ] (C1C4) (50) ] (C1H2) (31) ] (C1H3) (10)92 3069 31857999 304808243 34136 ] (C4H5) (57) ] (C4C6) (23) ] (C1C4) (14)93 3104 3237707 309500628 44771 ] (C1H2) (70) ] (C1H3) (11) ] (C4H5) (7)aAssignments and potential energy distribution (PED) (contributing ge 5) for vibrational normal mode Types of vibration ] stretching 120575 deformation oout-of-plane bending 120596 wagging y twisting 120588 rocking 120591 torsion w weak m medium sh shoulderbNormal mode number

Abso

rban

ce

Wavenumbers (cmminus1)

121

08060402

01200 1300 1400 1500 1600 1700 1800

17721295

13401357

1381

14081464

1619 1637 1686

1727

(a)

IR in

tens

ity (k

mm

ol) 50

40

30

20

10

0

Wavenumbers (cmminus1)1200 1250 1300 1350 1400 1450 1500 1550 1600 1650 1700 1750 1800

1244 12841301

1311

1307

134113731390

1394

1417

14631476

14841491

1656

1735

(b)

IR in

tens

ity (k

mm

ol) 50

40

30

20

10

0

Wavenumbers (cmminus1)

1227

1264

12421284

1266

12941302

13411373 1393

1419

14601476

14871489

16461731

1200 1250 1300 1350 1400 1450 1500 1550 1600 1650 1700 1750 1800

(c)

Figure 3 Comparison of the experimental IR (a) C=O and C=C stretching and CH bending region (1800ndash1200 cmminus1) with the appropriatetheoretical B3LYP6-311+Glowastlowast spectra ((b) and (c)) for s-cis and s-trans 2-ethylhexyl acrylate respectively

are well correlated to the calculated peaks in DFT for bothconformers see Tables 2 and 3

The shoulders in the infrared spectrum at 1025 1015 cmminus1of weak to medium intensities may be correlated to the bands1037 1015 cmminus1 for s-cis and 1015 988 cmminus1 for the s-trans

conformer These bands are ascribed to the CH out-of-planebending modes of the vinyl group

The remaining bands of weak intensity in the experimen-tal IR spectrum are 909 896 and 852 cmminus1 These bandsare close to the ones at 911 996 and 847 cmminus1 for the s-cis

12 Organic Chemistry International

121

08060402

0700 800 900 1000 1100 1200

727 770

811

952 869909 933

962 9841015 1025

1057

11161060

1191

Abso

rban

ce

Wavenumbers (cmminus1)

(a)

20

10

0

728776 783

825

848895

900911 940 975

1000

10131037

1008 1152 11581180

1016

1139

1156

1191

700 800 900 1000 1100 1200Wavenumbers (cmminus1)

IR in

tens

ity (k

mm

ol)

(b)

725

775783

827

846 896

900

940 965

993

1009

10131021

1066

10331051

1054

1079 11381156

1171

700 800 900 1000 1100 1200Wavenumbers (cmminus1)

20

10

0IR in

tens

ity (k

mm

ol)

(c)

Figure 4 Comparison of the experimental IR (a) CO stretching and CH bending region (1200ndash700 cmminus1) with the appropriate theoreticalB3LYP6-311+Glowastlowast spectra ((b) and (c)) for s-cis and s-trans 2-ethylhexyl acrylate respectively

conformation of the titlemolecule All the vibrational normalmodes in this region are not pure and the majority of themwere ascribed according to PED calculations to CH bending(for more details see Tables 2 and 3)

54 Region below 700 cmminus1 This spectral region includesthe bands associated with C=CndashC CndashOndashC O=CndashO OndashCndashC CndashCndashC and CndashCndashC bending and torsion modes aboutthe single bonds OndashC and CndashC The frequencies and PEDcalculations are presented in Tables 2 and 3 Comparing the23 first normal modes for the two conformers we notice thatthey have the same type of vibrational modes However thenormal modes 16 17 and 18 represent CCC bending in the s-trans andCHandCCC rockingmodes in the s-cis conformer

Due to the lack of experimental data on this region wecompare our calculated frequencies to some experimental IRbands of related molecules presented in the literature Thebands at 356 254 116 and 100 cmminus1 are close to the bandsat 349(A1015840) 244(A10158401015840) 114(A10158401015840) and 114 cmminus1 (A10158401015840) reported byDulce et al [28] From the same work the bands at 530 244114 and 114 cmminus1 belonging to A10158401015840 symmetry for the s-trans

methyl acrylate in liquid state are close to our calculatedbands in DFT at 542 244 116 and 106 cmminus1

6 Conclusions

Themid-IR spectrum of 2-ethylhexyl acrylate was measuredand interpreted with support of the DFTB3LYP6-311+Glowastlowastcalculated vibrational spectra followed by potential energydistribution analysis Assuming the s-cis and s-trans confor-mations we found two stable conformations close in theirenergies The fully optimized geometries of s-cis and s-transconformations by DFTB3LYP6-311+Glowastlowast were comparedwith the experimental and theoretical data presented in theliterature on the methyl acrylate molecule The compari-son shows a good agreement The experimental vibrationalspectrum is in good agreement with the theoretical spectracalculated for the two conformations Two neighbor bandsin the IR spectrum at 1619 and 1637 cmminus1 may be used ascharacteristic bands to locate and distinguish the existence ofone or both conformations

Organic Chemistry International 13

References

[1] M Salkind E H Riddle and R W Keefer ldquoAcrylates andmethacrylates ester manufacture and marketsrdquo Industrial ampEngineering Chemistry Research vol 51 no 11 pp 1328ndash13341959

[2] K S Anseth S M Newman and C N Bowman ldquoPolymericdental composites properties and reaction behavior of multi-methacrylate dental restorationsrdquo Advances in Polymer Sciencevol 122 pp 176ndash217 1995

[3] J G Kloosterboer ldquoNetwork formation by chain crosslink-ing photopolymerization and its application in electronicsrdquoAdvances in Polymer Science vol 84 pp 1ndash61 1988

[4] K Matyjaszewski Y Gnanou and L Leibler MacromolecularEngineering vol 1 Wiley-VCH Weinheim Germany 2007

[5] M Orgill B L Baker and N L Owen ldquoFTIR studies ofconformational isomerism in acrylates and acrylic acidsrdquo Spec-trochimica Acta A vol 55 no 5 pp 1021ndash1024 1999

[6] M Salkind ldquoReaches into the marketrdquo Industrial amp EngineeringChemistry Research vol 56 pp 62ndash110 1964

[7] E Takacs K Dajka and L Wojnarovits ldquoStudy of high-energyradiation initiated polymerization of butyl acrylaterdquo RadiationPhysics and Chemistry vol 63 no 1 pp 41ndash44 2002

[8] H Yu J Peng M Zhai J Li G Wei and J Qiao ldquoRadiation-induced copolymerization of styrenen-butyl acrylate in thepresence of ultra-fine powdered styrene-butadiene rubberrdquoRadiation Physics and Chemistry vol 76 no 11-12 pp 1736ndash1740 2007

[9] P F Canamero J Luis de la Fuente and M Fermandez-GarcıaldquoCuring kinetic study using a well-controlled multifunctionalcopolymer based on glycidyl methacrylaterdquo European PolymerJournal vol 45 no 9 pp 2665ndash2673 2009

[10] DMathew C P ReghunadhanNair and K N Ninan ldquoPendantcyanate functional vinyl polymers and imidophenolic-triazinesthereof synthesis and thermal propertiesrdquo European PolymerJournal vol 36 no 6 pp 1195ndash1208 2000

[11] S Mitra S Chattopadhyay S Sabharwal and A K BhowmickldquoElectron beam crosslinked gels-Preparation characterizationand their effect on the mechanical dynamic mechanical andrheological properties of rubbersrdquoRadiation Physics and Chem-istry vol 79 no 2 pp 289ndash296 2010

[12] P Canamero-Martınez M Fermandez-Garcıa and J Luis de laFuente ldquoRheological cure characterization of a polyfunctionalepoxy acrylic resinrdquo Reactive and Functional Polymers vol 70no 10 pp 761ndash766 2010

[13] F Chu T McKenna and S Lu ldquoCuring kinetics of an acrylicresinepoxy resin system using dynamic scanning calorimetryrdquoEuropean Polymer Journal vol 33 no 6 pp 837ndash840 1997

[14] M C Douskey M S Gebhard A V McCormick et alldquoSpectroscopic studies of a novel cyclic oligomer with pendantalkoxysilane groupsrdquo Progress in Organic Coatings vol 45 no2-3 pp 145ndash157 2002

[15] R J Day P A Lovell and A A Wazzan ldquoToughened car-bonepoxy composites made by using coreshell particlesrdquoComposites Science andTechnology vol 61 no 1 pp 41ndash56 2001

[16] K Bolton D G Lister and J Sheridan ldquoRotational isomerismbarrier to internal rotation and electric dipole moment ofacrylic acid bymicrowave spectroscopyrdquo Journal of the ChemicalSociety Faraday Transactions 2 vol 70 pp 113ndash123 1974

[17] S W Charles F C Cullen N L Owen and G A WilliamsldquoInfrared spectrum and rotational isomerism of acrylic acidrdquoJournal of Molecular Structure vol 157 no 1ndash3 pp 17ndash25 1987

[18] K Bolton N L Owen and J Sheridan ldquoMicrowave spectra ofrotational isomers of acrylic acidrdquoNature vol 218 no 5138 pp266ndash267 1968

[19] G Williams N L Owen and J Sheridan ldquoSpectroscopicstudies of some substitutedmethyl formatesmdashpart 1microwavespectra and internal rotation barriers of methyl-fluoroformate-propiolate -cyanoformate -acrylate and -acetaterdquo Transac-tions of the Faraday Society vol 67 pp 922ndash949 1971

[20] T Tsuji H Ito H Takeuchi and S Konaka ldquoMolecularstructure and conformation ofmethylmethacrylate determinedby gas electron diffractionrdquo Journal of Molecular Structure vol475 no 1 pp 55ndash63 1999

[21] T Egawa S Maekawa H Fujiwara Takeuchi H Takeuchi andS Konaka ldquoMolecular structure and conformation of methylacrylate a gas electron diffraction study augmented by ab initiocalculation and rotational constantsrdquo Molecular Structure andSpectroscopy vol 352 pp 193ndash201 1995

[22] A Virdi V P Gupta and A Sharma ldquoAb initio studies onconformation vibrational and electronic spectra of methylmethacrylaterdquo Journal ofMolecular Structure vol 634 no 5 pp53ndash65 2003

[23] B L Baker M Orgill N L Owen et al ldquoThe molecularconformation of methyl methacrylatemdashan infrared and abinitio studyrdquo Journal of Molecular Structure vol 356 no 2 pp95ndash104 1995

[24] A N Mitra and I Santhanan ldquoRelativistic qqq spectra fromBethe-Salpeter premisesrdquo Physics Letters B vol 104 no 1 pp62ndash66 1981

[25] K Fan and J E Boggs ldquoRotational isomerism of acrylic acidrdquoJournal of Molecular Structure vol 157 no 1ndash3 pp 31ndash41 1987

[26] P Carmona and J Moreno ldquoThe infrared spectra and structureof methyl acrylaterdquo Journal of Molecular Structure vol 82 no3-4 pp 177ndash185 1982

[27] R J Loncharich T R Schwartz and K N Houk ldquoTheoreticalstudies of conformations of acrolein acrylic acid methyl acry-late and their Lewis acid complexesrdquo Journal of the AmericanChemical Society vol 109 no 1 pp 14ndash23 1987

[28] M Dulce G Faria J J C Teixeira-Dias and R FaustoldquoVibrational spectra and structure of methyl trans-crotonaterdquoVibrational Spectroscopy vol 2 no 2-3 pp 43ndash60 1991

[29] J J C Teixeira-Dias and R Fausto ldquoMolecular structure ofmethyl acrylate the high energy s-trans-(CO) conformerrdquoJournal of Molecular Structure vol 282 no 1-2 pp 123ndash1291993

[30] A J Bowles W O George and D B Cunliffe-Jones ldquoConfor-mations of some120572120573-unsaturated carbonyl compoundsmdashpart IIinfrared and Raman spectra of methyl and ethyl acrylates andtranscrotonatesrdquo Journal of the Chemical Society B pp 1070ndash1075 1970

[31] A D Becke ldquoDensity-functional thermochemistry IIIThe roleof exact exchangerdquoThe Journal of Chemical Physics vol 98 no7 pp 5648ndash5652 1993

[32] C Lee W Yang and R G Parr ldquoDevelopment of the Colle-Salvetti correlation-energy formula into a functional of theelectron densityrdquo Physical Review B vol 37 no 2 pp 785ndash7891988

[33] H Yoshida K Takeda J Okamura A Ehara and H MatsuuraldquoA new approach to vibrational analysis of large molecules bydensity functional theory wavenumber-linear scalingmethodrdquoJournal of Physical Chemistry A vol 106 no 14 pp 3580ndash35862002

14 Organic Chemistry International

[34] H Yoshida A Ehara and H Matsuura ldquoDensity functionalvibrational analysis using wavenumber-linear scale factorsrdquoChemical Physics Letters vol 325 no 4 pp 477ndash483 2000

[35] M J Frisch G W Trucks H B Schlegel et al Gaussian 03Revision B 01 Gaussian Pittsburgh Pa USA 2003

[36] J M L Martin and C Van Alsenoy GAR2PED A Program toObtain a Potential Energy Distribution from a Gaussian ArchiveRecord University of Antwerp 2009

[37] P Pulay G Fogarasi F Pang and J E Boggs ldquoSystematicab initio gradient calculation of molecular geometries forceconstants and dipole moment derivativesrdquo Journal of theAmerican Chemical Society vol 101 no 10 pp 2550ndash2560 1979

[38] S Mishra D Chaturvedi N Kumar P Tandon and H WSiesler ldquoAn ab initio and DFT study of structure and vibrationalspectra of 120574 form of Oleic acid comparison to experimentaldatardquo Chemistry and Physics of Lipids vol 163 no 2 pp 207ndash217 2010

[39] W O George D V Hassid and W F Maddams ldquoConfor-mations of some 120572120573-unsaturated carbonyl compoundsmdashpartIII infrared solution spectra of methyl [2H3]methyl ethyland [2H5]ethyl acrylates and trans-crotonatesrdquo Journal of theChemical Society Perkin Transactions 2 no 4 pp 400ndash4041972

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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CatalystsJournal of

Page 7: Research Article Molecular Structure and Vibrational Spectra ...e molecular geometry, vibrational frequencies, and infrared intensities have been calculated by using density functional

Organic Chemistry International 7

Table 2 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

43 mdash 11505508 113898319 19252 120588 (C9C12H13) (96)

44 1116 (w) 11685589 115646723 118316 120575 (C12C21C24) (67) 120588 (C14C12H13) (9) 120588 (O8C9C12) (7)120575 (C14C12C21) (67)

45 1060 (sh) 11856606 117306145 00857 120575 (C9C12C14) (63) 120588 (C30H3) (26) 120575 (C12C14C17) (6)46 1191 12051044 11919167 6261232 120588 (C6C4H5) (87)47 mdash 12437853 12293901 03621 y (C21H2) (94) y (C27H2) (5)48 mdash 12586429 124377093 10505 120588 (C9H2) (76) 120596 (C21H2) (23)49 mdash 12817118 12660853 07178 y (C14H2) (55) 120596 (C21H2) (44)50 mdash 13003301 128408198 13337 120596 (C21H2) (93)

51 mdash 13179028 130105761 111581 120596 (C24H2) (24) 120588 (C9C12H13) (17) y (C14H2) (13) 120596(C27H2) (7) 120588 (C6O8C9) (5)

52 1272 13245992 130752384 683227 y (C27H2) (37) 120588 (C9C12H13) (29) y (C21H2) (22) y(C14H2) (6)

53 1295 13282386 131103753 60034 y (C27H2) (93)54 mdash 13381682 132062195 05711 y (C24H2) (70) y (C27H2) (28)55 1340 13610156 134266291 13124 120596 (C21H2) (78) 120596 (C9H2) (21)56 mdash 13812224 13621423 04732 120588 (C9C12C21) (78) 120596 (C21H2) (21)57 1357 13942309 137467547 33349 120596 (C9H2) (95)58 mdash 14045719 138463467 45032 120596 (C24H2) (95) 120596 (C21H2) (5)59 1381 14109338 139075996 73272 120596 (C21H2) (97)60 mdash 14141585 139386422 23703 120596 (C21H2) (99)61 mdash 14180649 139762426 04645 120596 (C21H2) (93) 120596 (C14H2) (6)62 1408 1437761 141657487 831633 120596 (C9H2) (49) 120596 (C21H2) (26) 120575 (CH2) (20)

63 mdash 14861635 146309161 10310 120575 (C21H2) (40) 120575 (C24H2) (20) 120575 (C12C21C24) (12) 120575(C14H2) (7)

64 mdash 14883957 1465235 10310 120575 (C27H2) (29) 120575 (C21H2) (28) 120575 (C24H2) (18) 120575(C12C21C24) (14) 120575 (C14H2) (10) 120575 (C27H2) (10)

65 mdash 1492293 146897685 13617 120575 (C21H2) (67) 120575 (C27H2) (11) 120575 (C14H2) (7)66 mdash 14999113 147628987 83925 120575 (C30H3) (88) 120575 (C27H2) (10)

67 mdash 15017672 147807111 43738 120575 (C21H2) (29) 120575 (C30H3) (28) 120575 (C24H2) (15) 120575(C21C12H13) (11) 120575 (C14H2) (6)

68 mdash 1503707 147993276 35078 120575 (C27H2) (31) 120575 (C21H2) (29) 120575 (C9H2) (18)

69 1464 15093473 148534511 99123 120575 (C17H3) (27) 120575 (C27H2) (26) 120575 (C21H2) (10) 120575(C12C21C24) (8) 120575 (C24H2) (7) 120575 (C12C14C21) (6)

70 mdash 15106836 148662726 108575 120575 (C21H2) (83) 120575 (C27H2) (10)

71 mdash 15154657 149121508 60184 120575 (C24H2) (42) 120575 (C21C24C27) (25) 120575 (C27H2) (13) 120575(C21H2) (10)

72 1637 16875503 165581242 269151 ] (C1C4) (87) 120575 (C1H2) (7)

73 1727 1770955 173524092 2434946 ] (C6O7) (80) 120575 (O8C9H12) (7) 120575 (C21H2) (5) ] (C4C6)(5)

74 mdash 29973914 287702371 27860 ] (C21H22) (45) ] (C14H2) (33) ] (C12H13) (14)75 mdash 29998142 287923075 17988 ] (C21H2) (76) ] (C24H2) (14)

76 mdash 30020159 288123622 138469 ] (C27H2) (33) ] (C24H2) (32) ] (C30H31) (22) ](C21H2) (6)

77 mdash 30058916 288476609 146381 ] (C21H2) (74) ] (C14H2) (14) ] (C12H13) (5)78 2861 30145745 289267245 457319 ] (C12H13) (63) ] (C30H31) (31)79 2875 30180275 289581595 559324 ] (C30H31) (98)80 mdash 30238407 290110723 222942 ] (C17H19) (58) ] (C17H18) (29)

81 mdash 30261436 290320306 164278 ] (C17H19) (32) ] (C14H2) (29) ] (C17H18) (15) ](C30C31) (8) ] (C21H2) (6)

82 mdash 30348324 291110906 351134 ] (C14H2) (96)

8 Organic Chemistry International

Table 2 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

83 mdash 30419158 291755246 160910 ] (C27H2) (38) ] (C9H2) (20) ] (C14H2) (19) ] (C21H2)(6) ] (C24H) (6)

84 mdash 30431697 29186929 145616 ] (C27H2) (47) ] (C9H2) (26) ] (C24H2) (10) ] (C14H2)(7)

85 mdash 3062906 293663657 465673 ] (C21H2) (55) ] (C27H2) (25) ] (C24H2) (9) ] (C12H13)(5)

86 2931 30788255 295110087 858987 ] (C27H2) (62) ] (C27H30) (10) ] 295503236 (C30H3)(9) ] (C9H2) (6) ] (C17H19) (6)

87 mdash 30831541 295503236 455349 ] (C30H31) (99)

88 mdash 30845244 295627682 351235 ] (C17H19) (67) ] (C17C19) (67) ] (C17C18) (17) ](C30H31) (15)

89 mdash 30879105 29593517 195239 ] (C9H2) (63) ] (O8C9) (16) ]-(C12H13) (11) ] (C17C19)(6)

90 2961 30931423 296410191 561433 ] (C17H19) (38) ] (C9H2) (26) ] (C17H20) (12) ](C14H2) (10) ] (C17H18) (9)

91 3038 31428663 300920422 51952 ] (C1C4) (45) ] (C1H2) (38) ] (C1H3) (9)92 mdash 3185092 304744188 32650 ] (C1H2) (95)93 3104 32359105 309338372 23617 ] (C4H5) (67) ] (C1H2) (22) ] (C1H3) (6)aAssignments and potential energy distribution (PED) (contributing ge 5) for vibrational normal mode Types of vibration ] stretching 120575 deformation oout-of-plane bending 120596 wagging y twisting 120588 rocking 120591 torsion w weak m medium sh shoulderbNormal mode number

1655 cmminus1 for s-cis conformer (Figure 3(b)) and 1647 cmminus1 forthe s-trans conformer (Figure 3(c)) The band at 1637 cmminus1may be used to definitely indicate that conformer with s-transarrangement of acrylic moiety is present or not in the liquid2-ethylhexyl acrylate

In the region from 1500 to 1200 cmminus1 in the experimen-tal spectrum (Figure 3) there are four bands of mediumintensity located at 1464 1408 1295 and 1272 cmminus1 Thebands of weak intensity of account of three are locatedat 1381 1357 and 1340 cmminus1 The calculated frequencies inthis region for the s-cis and s-trans conformations haveclose energies for each normal mode and the differencesdo not exceed 5 cmminus1 Based on the assignments reportedby Dulce et al [28] and our PED calculations we haveascribed the theoretical frequencies 1485 cmminus1 (s-cis) and1484 cmminus1 (s-trans) to the experimental band at 1464 cmminus1and they are representing a C

17H3symmetric bending The

calculated frequencies at 1479 1478 and 1476 cmminus1 may becontributed to the experimental band at 1464 cmminus1 due toits relatively large middle width of about 75 cmminus1 Mishra etal [38] have reported the experimental and the theoreticalIR spectra of 120574 form of oleic acid many peaks reported inthe region 1370 to 1220 cmminus1 for the CH

2carboxyl-sided

chain correspond approximately to those we found in ourspectrum from 1400 to 1200 cmminus1 and all of them may beassigned to CH

2deformation The assignment is based on

the bands intensities we found a good correlation betweenthe experimental and the theoretical spectra One shouldpoint out that the very intense bands predicted at 1267 and

1264 cmminus1 for s-trans form reproduce well the asymmetricshape of the experimental band at 1272 cmminus1 For bandsassignment see Tables 2 and 3

53 The CO Stretching and CH Bending Vibrations (1200ndash700 cmminus1 Figure 4) In this region in the IR spectrum thereis one very strong band at 1192 cmminus1 with weak shoulder at1160 cmminus1 and four medium intensity bands 1057 984 962shoulder at 933 and 811 cmminus1 The bands at 1116 1025 909896 852 770 and 727 cmminus1 (shoulder at 748 cmminus1) are ofweak intensity (Figure 4) Based on PEDs and intensities ofthe calculated frequencies we correlate the two intense bandsat 1192 and 1156 cmminus1 for the more stable and the less stableconformers to the band at 1191 cmminus1 in the experimentalIR spectrum The medium bands in IR spectrum are wellreproduced by the calculated peaks at 1079 999 976 941 and811 cmminus1 for the s-cis conformer and 1067 993 940 911 and828 cmminus1 for the s-trans conformer They may be ascribed toCH2rocking C

1H2wagging CCH rocking O

8C9 and C

1H2

twisting The peaks predicted by DFT at 728 and 783 cmminus1 ins-cis form and the peaks at 726 and 782 cmminus1 in the s-transformmay be correlated to the bands at 727 and 770 cmminus1 andthey are assigned to the CH

2deformations of the alkyl sides

of the title moleculeIn the IR spectra of 2-ethylhexyl acrylate reported in

this work there are a few bands with weak to very weakintensity which do not appear in the IR spectra of methylacrylate reported by Dulce et al [28] and George et al [39]These bands appear at 1157 1120 1052 and 1022 cmminus1 and they

Organic Chemistry International 9

Table 3 Frequencies and PEDs of s-trans 2-ethylhexyl acrylate

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

1 mdash 295569 2979981 13888 120591 (C21C24) (95)2 mdash 312922 3154848 12915 120591 (C21C24) (100)3 mdash 453002 4566086 00227 120591 (C21C24) (91) 120591 (O8C9) (6)4 mdash 69075 6959818 00113 120591 (C21C24) (98)5 mdash 916561 9231657 07304 120588 (C14H2) (64) 120591 (C9C12) (19) 120591 (C24C21) (15)6 mdash 106795 10753821 00788 120591 (C12C14) (92)7 mdash 116406 11719786 04606 120591 (O8C9) (90) 120591 (C21C24) (7)8 mdash 128002 12884855 07652 120591 (C21C24) (99)9 mdash 1377311 13862015 00737 120591 (C24C21) (94)10 mdash 1886176 18967867 24795 120591 (C24C21) (53) O (O8C9) (44)11 mdash 1964898 19756995 22280 120588 (C9H2) (82) 120591 (C9C12) (13)12 mdash 2346 23574391 17535 120588 (C30H3) (90) 120591 (C21C24) (7)13 mdash 2495865 25074252 32507 120588 (C30H3) (78) 120591 (C12C21) (19)14 mdash 2623636 26352416 12259 120588 (C9H2) (72) 120588 (C17H3) (22)15 mdash 2741636 27532362 05126 120591 (C12C21) (96)16 mdash 3352283 33631302 04554 120575 (C21C12C14) (93)17 mdash 3546136 355649 01655 120575 (C21C12C24) (95)18 mdash 406411 40725451 25402 120575 (C9C12C14) (92)19 mdash 4713032 47178287 10320 120588 (C9C12C14) (70) 120575 (C9C12C21) (12) 120588 (C14H2) (11)20 mdash 5098943 51009251 04733 y (C1H2) (86) O (C6O8) (12)

21 mdash 5140157 51418098 73067 120588 (C12C14C17) (38) 120588 (C9C12C21) (15) 120588 (C12C21) (14)120588 (C14C12H13) (13) 120588 (C1H2) (8) 120575 (C12C21C24) (7)

22 mdash 550859 55070531 22808 120588 (C9C12C14) (78) 120588 (C6O8C9) (9) 120588 (C1H2) (6)23 mdash 6360175 6349572 19146 120588 (O8C9C12) (97)24 727 (m) 7284338 72612214 43677 120588 (C9C12C21) (92)25 mdash 778027 77492902 06843 120588 (C9C12C21) (98)26 770 (m) 785397 78217532 18732 120588 (C21H2) (59) 120588 (C14H2) (36)27 811 (m) 8321364 82808904 215147 y (C1H2) (94) 120588 (C9H2) (5)

28 852 (w) 8501904 84580503 34731 120588 (C9C12C21) (47) 120588 (C9H2) (27) 120588 (C1H2) (15) ](C14C17) (5)

29 896 (w) 9017561 8963468 09206 120588 (C9C12C21) (73) 120588 (C21C24C27) (14)30 909 (w) 9065632 90105403 13451 120588 (C9C12C21) (46) 120588 (C9H2) (35) 120588 (C12C14C17) (9)31 933 (sh) 9170283 91129911 76343 120588 (O7C6O8) (86) 120588 (C9H2) (10)32 962 (m) 9470255 94064585 60649 120588 (C6O8C9) (99)33 mdash 9726775 96571834 70484 120588 (C6O8C9) (99)

34 984 (m) 10012212 99359199 344957 120596 (C1H2) (52) ] (C1C4) (15) 120575 (C4C6O8) (15) ] (C12C21)(15)

35 1015 (sh) 10171676 100915249 70006 ] (C12C21) (92)36 mdash 10219635 101383071 35045 ] (C21C24) (85) 120575 (C9C12O14) (9)37 1025 (sh) 10299052 102157589 185130 y (C1H2) (97)38 mdash 1040755 103215388 03554 ] (C21C24) (70) ] (C9C12) (14) y (C21H2) (5)39 mdash 10608287 105171458 55936 y (C21H2) (58) 120588 (C14C12H13) (29) 120588 (C14H2) (7)40 mdash 10640573 105485945 188097 ] (C21C24) (88) ] (C14C17) (8)41 1057 (m) 10767989 106726727 1926571 ] (C9O8) (82) ] (C14C17) (13)42 1060 (sh) 10895069 10796371 46500 120588 (C9H2) (40) 120575 (C9C12C21) (30) 120596 (C27H2) (25)43 1116 (w) 11506075 113903825 14631 120588 (C9C12H13) (51) 120575 (C9C12C21) (42)44 1191 11682621 115617915 32253 120588 (C14C12H13) (72) 120596 (C21H2) (16) 120588 (O8C9C12) (9)45 mdash 11850265 117244634 01695 120575 (C9C12C14) (94)

10 Organic Chemistry International

Table 3 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

46 mdash 1242923 122855525 17298 y (C21H2) (89)47 mdash 1258238 124337912 11546 120588 (C9C12C21) (35) 120596 (C21H2) (35) 120596 (C9H2) (27)48 mdash 12801017 126452842 779146 120596 (C21H2) (47) 120588 (C9C12C21) (37) 120588 (C9H2) (27)49 1272 1283202 126752616 3516365 120596 (C21H2) (60) y (C14H2) (27) y (C9H2) (10)50 mdash 12991286 128292094 44292 y (C9H2) (72) y (C21H2) (26)51 1295 13117811 129514505 72842 y (C14H2) (99)52 mdash 131875 130187577 68204 y (C14H2) (100)53 mdash 13264691 13093292 01479 y (C21H2) (97)54 mdash 13362199 131874163 04090 y (C24H2) (94) y (C21H2) (5)55 1340 1359997 134168063 10793 120596 (C21H2) (86) 120588 (C21C12C14) (7) 120596 (C9H2) (5)56 mdash 13800145 136097825 04801 120588 (C9C12C21) (43) 120575 (C9H12) (28) 120596 (C21H2) (25)

57 1357 13931134 137359902 28872 120596 (C9H2) (50) 120596 (C14H2) (23) 120575 (C21C12H13) (12) 120596(C21H2) (86)

58 mdash 14043849 138445461 09476 120596 (C21H2) (86) 120596 (C9H2) (12)59 mdash 14119509 139173911 08054 120596 (C9H2) (85) 120596 (C21H2) (14)60 1381 14145333 1394225 50233 120596 (C21H2) (54) 120596 (C9H2) (45)61 mdash 14173104 139689807 08100 120596 (C21H2) (89) 120596 (C9H2) (8)62 1408 14414398 142011302 305726 120596 (C9H2) (93) 120596 (C21H2) (5)

63 mdash 14831028 146015241 20326 120575 (C9H2) (38) 120575 (C21C12H13) (18) 120575 (C24C21C12) (15) 120575(C14H2) (13) 120575 (C24H2) (7) 120575 (C21H2) (6)

64 mdash 14876468 146451591 04300 120575 (C21C12H13) (33) 120575 (C27H2) (28) 120575 (C24H2) (20) 120575(C21H2) (10)

65 mdash 14916884 14683964 12432 120575 (C21H2) (54) 120575 (C9H2) (21) 120575 (C27H2) (11)

66 mdash 15000764 147644833 24692 120575 (C24H2) (32) 120575 (C21C12H13) (24) 120575 (C27H2) (8) 120575(C30H3) (8) 120575 (C21H2) (6)

67 mdash 1500718 147706413 70795 120575 (C30H3) (75) 120575 (C9H2) (11) 120575 (C27H2) (6)68 mdash 15025266 147879993 89950 120575 (C9H2) (74) 120575 (C17H3) (21)

69 1464 15081671 148421269 98400 120575 (C27H2) (26) 120575 (C30H3) (22) 120575 (C21H2) (14) 120575(C17H3) (14) 120575 (C24H2) (11)

70 mdash 15116225 148752807 105533 120575 (C21H2) (73) 120575 (C21C12H13) (6) 120575 (C24H2) (5) 120575(C17H3) (5)

71 mdash 1514069 14898752 56625 120575 (C24H2) (30) 120575 (C21H2) (29) 120575 (C21C24C27) (20) 120575(C27H2) (9)

72 1619 16787098 164738009 287096 ] (C1C4) (52) ] (C4C6) (22) 120575 (C9C12H13) (11) 120575(C21H2) (8)

73 1727 17668533 173134006 3155882 120575 (C9C12C21) (63) ] (C4C6) (16) 120575 (C21H2) (6) ](C6O7) (6)

74 mdash 2995932 287569419 20873 ] (C24H2) (35) ] (C14H2) (34) ] (C21H2) (25)

75 mdash 2998467 287800355 06759 ] (C24H2) (40) ] (C12H13) (29) ] (C21H2) (12) ](C14H2) (10)

76 mdash 3001649 288090203 135187 ] (C21H2) (92)77 mdash 30053152 288424116 132101 ] (C24H2) (87) ] (C24H2) (8)78 2861 3013385 289158948 585964 ] (C21H2) (45) ] (C30C32) (36) ] (C12H13) (12)79 2875 30178939 289569433 472871 ] (C30C32) (96)80 mdash 30236248 290091073 211397 ] (C14H12) (46) ] (C17H19) (32) ] (C17H18) (17)

81 mdash 30260401 290310887 159088 ] (C12H13) (30) ] (C17H19) (27) ] (C17H18) (13) ](C30C32) (12)

82 mdash 303455 291085214 329164 ] (C21H2) (66) ] (C14H2) (28)83 mdash 30404085 291618149 40314 ] (C21H2) (55) ] (C30H32) (27) ] (C12H13) (7)84 mdash 30437899 291925696 263738 ] (C21H2) (98)85 mdash 30609167 293482854 503404 ] (C21H2) (85) ] (C30C32) (12)86 2931 30786333 295092629 824131 ] (C30C32) (95)

Organic Chemistry International 11

Table 3 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

87 mdash 30833975 295525341 441245 ] (C30C32) (93)88 mdash 30842781 295605315 369537 ] (C17H19) (67) ] (C17H18) (18) ] (C21H2) (9)

89 mdash 30889498 296029541 151201 ] (C21H2) (52) ] (C9H2) (14) ] (C12H13) (14) ] (C14H2)(8) ] (C17H19) (7)

90 2961 30930704 296403663 595099 ] (C17H19) (36) ] (C14H2) (28) ] (C17H20) (10) ](C21H2) (10) ] (C17H18) (8) ] (C9H2) (6)

91 3038 31462567 301227655 52018 ] (C1C4) (50) ] (C1H2) (31) ] (C1H3) (10)92 3069 31857999 304808243 34136 ] (C4H5) (57) ] (C4C6) (23) ] (C1C4) (14)93 3104 3237707 309500628 44771 ] (C1H2) (70) ] (C1H3) (11) ] (C4H5) (7)aAssignments and potential energy distribution (PED) (contributing ge 5) for vibrational normal mode Types of vibration ] stretching 120575 deformation oout-of-plane bending 120596 wagging y twisting 120588 rocking 120591 torsion w weak m medium sh shoulderbNormal mode number

Abso

rban

ce

Wavenumbers (cmminus1)

121

08060402

01200 1300 1400 1500 1600 1700 1800

17721295

13401357

1381

14081464

1619 1637 1686

1727

(a)

IR in

tens

ity (k

mm

ol) 50

40

30

20

10

0

Wavenumbers (cmminus1)1200 1250 1300 1350 1400 1450 1500 1550 1600 1650 1700 1750 1800

1244 12841301

1311

1307

134113731390

1394

1417

14631476

14841491

1656

1735

(b)

IR in

tens

ity (k

mm

ol) 50

40

30

20

10

0

Wavenumbers (cmminus1)

1227

1264

12421284

1266

12941302

13411373 1393

1419

14601476

14871489

16461731

1200 1250 1300 1350 1400 1450 1500 1550 1600 1650 1700 1750 1800

(c)

Figure 3 Comparison of the experimental IR (a) C=O and C=C stretching and CH bending region (1800ndash1200 cmminus1) with the appropriatetheoretical B3LYP6-311+Glowastlowast spectra ((b) and (c)) for s-cis and s-trans 2-ethylhexyl acrylate respectively

are well correlated to the calculated peaks in DFT for bothconformers see Tables 2 and 3

The shoulders in the infrared spectrum at 1025 1015 cmminus1of weak to medium intensities may be correlated to the bands1037 1015 cmminus1 for s-cis and 1015 988 cmminus1 for the s-trans

conformer These bands are ascribed to the CH out-of-planebending modes of the vinyl group

The remaining bands of weak intensity in the experimen-tal IR spectrum are 909 896 and 852 cmminus1 These bandsare close to the ones at 911 996 and 847 cmminus1 for the s-cis

12 Organic Chemistry International

121

08060402

0700 800 900 1000 1100 1200

727 770

811

952 869909 933

962 9841015 1025

1057

11161060

1191

Abso

rban

ce

Wavenumbers (cmminus1)

(a)

20

10

0

728776 783

825

848895

900911 940 975

1000

10131037

1008 1152 11581180

1016

1139

1156

1191

700 800 900 1000 1100 1200Wavenumbers (cmminus1)

IR in

tens

ity (k

mm

ol)

(b)

725

775783

827

846 896

900

940 965

993

1009

10131021

1066

10331051

1054

1079 11381156

1171

700 800 900 1000 1100 1200Wavenumbers (cmminus1)

20

10

0IR in

tens

ity (k

mm

ol)

(c)

Figure 4 Comparison of the experimental IR (a) CO stretching and CH bending region (1200ndash700 cmminus1) with the appropriate theoreticalB3LYP6-311+Glowastlowast spectra ((b) and (c)) for s-cis and s-trans 2-ethylhexyl acrylate respectively

conformation of the titlemolecule All the vibrational normalmodes in this region are not pure and the majority of themwere ascribed according to PED calculations to CH bending(for more details see Tables 2 and 3)

54 Region below 700 cmminus1 This spectral region includesthe bands associated with C=CndashC CndashOndashC O=CndashO OndashCndashC CndashCndashC and CndashCndashC bending and torsion modes aboutthe single bonds OndashC and CndashC The frequencies and PEDcalculations are presented in Tables 2 and 3 Comparing the23 first normal modes for the two conformers we notice thatthey have the same type of vibrational modes However thenormal modes 16 17 and 18 represent CCC bending in the s-trans andCHandCCC rockingmodes in the s-cis conformer

Due to the lack of experimental data on this region wecompare our calculated frequencies to some experimental IRbands of related molecules presented in the literature Thebands at 356 254 116 and 100 cmminus1 are close to the bandsat 349(A1015840) 244(A10158401015840) 114(A10158401015840) and 114 cmminus1 (A10158401015840) reported byDulce et al [28] From the same work the bands at 530 244114 and 114 cmminus1 belonging to A10158401015840 symmetry for the s-trans

methyl acrylate in liquid state are close to our calculatedbands in DFT at 542 244 116 and 106 cmminus1

6 Conclusions

Themid-IR spectrum of 2-ethylhexyl acrylate was measuredand interpreted with support of the DFTB3LYP6-311+Glowastlowastcalculated vibrational spectra followed by potential energydistribution analysis Assuming the s-cis and s-trans confor-mations we found two stable conformations close in theirenergies The fully optimized geometries of s-cis and s-transconformations by DFTB3LYP6-311+Glowastlowast were comparedwith the experimental and theoretical data presented in theliterature on the methyl acrylate molecule The compari-son shows a good agreement The experimental vibrationalspectrum is in good agreement with the theoretical spectracalculated for the two conformations Two neighbor bandsin the IR spectrum at 1619 and 1637 cmminus1 may be used ascharacteristic bands to locate and distinguish the existence ofone or both conformations

Organic Chemistry International 13

References

[1] M Salkind E H Riddle and R W Keefer ldquoAcrylates andmethacrylates ester manufacture and marketsrdquo Industrial ampEngineering Chemistry Research vol 51 no 11 pp 1328ndash13341959

[2] K S Anseth S M Newman and C N Bowman ldquoPolymericdental composites properties and reaction behavior of multi-methacrylate dental restorationsrdquo Advances in Polymer Sciencevol 122 pp 176ndash217 1995

[3] J G Kloosterboer ldquoNetwork formation by chain crosslink-ing photopolymerization and its application in electronicsrdquoAdvances in Polymer Science vol 84 pp 1ndash61 1988

[4] K Matyjaszewski Y Gnanou and L Leibler MacromolecularEngineering vol 1 Wiley-VCH Weinheim Germany 2007

[5] M Orgill B L Baker and N L Owen ldquoFTIR studies ofconformational isomerism in acrylates and acrylic acidsrdquo Spec-trochimica Acta A vol 55 no 5 pp 1021ndash1024 1999

[6] M Salkind ldquoReaches into the marketrdquo Industrial amp EngineeringChemistry Research vol 56 pp 62ndash110 1964

[7] E Takacs K Dajka and L Wojnarovits ldquoStudy of high-energyradiation initiated polymerization of butyl acrylaterdquo RadiationPhysics and Chemistry vol 63 no 1 pp 41ndash44 2002

[8] H Yu J Peng M Zhai J Li G Wei and J Qiao ldquoRadiation-induced copolymerization of styrenen-butyl acrylate in thepresence of ultra-fine powdered styrene-butadiene rubberrdquoRadiation Physics and Chemistry vol 76 no 11-12 pp 1736ndash1740 2007

[9] P F Canamero J Luis de la Fuente and M Fermandez-GarcıaldquoCuring kinetic study using a well-controlled multifunctionalcopolymer based on glycidyl methacrylaterdquo European PolymerJournal vol 45 no 9 pp 2665ndash2673 2009

[10] DMathew C P ReghunadhanNair and K N Ninan ldquoPendantcyanate functional vinyl polymers and imidophenolic-triazinesthereof synthesis and thermal propertiesrdquo European PolymerJournal vol 36 no 6 pp 1195ndash1208 2000

[11] S Mitra S Chattopadhyay S Sabharwal and A K BhowmickldquoElectron beam crosslinked gels-Preparation characterizationand their effect on the mechanical dynamic mechanical andrheological properties of rubbersrdquoRadiation Physics and Chem-istry vol 79 no 2 pp 289ndash296 2010

[12] P Canamero-Martınez M Fermandez-Garcıa and J Luis de laFuente ldquoRheological cure characterization of a polyfunctionalepoxy acrylic resinrdquo Reactive and Functional Polymers vol 70no 10 pp 761ndash766 2010

[13] F Chu T McKenna and S Lu ldquoCuring kinetics of an acrylicresinepoxy resin system using dynamic scanning calorimetryrdquoEuropean Polymer Journal vol 33 no 6 pp 837ndash840 1997

[14] M C Douskey M S Gebhard A V McCormick et alldquoSpectroscopic studies of a novel cyclic oligomer with pendantalkoxysilane groupsrdquo Progress in Organic Coatings vol 45 no2-3 pp 145ndash157 2002

[15] R J Day P A Lovell and A A Wazzan ldquoToughened car-bonepoxy composites made by using coreshell particlesrdquoComposites Science andTechnology vol 61 no 1 pp 41ndash56 2001

[16] K Bolton D G Lister and J Sheridan ldquoRotational isomerismbarrier to internal rotation and electric dipole moment ofacrylic acid bymicrowave spectroscopyrdquo Journal of the ChemicalSociety Faraday Transactions 2 vol 70 pp 113ndash123 1974

[17] S W Charles F C Cullen N L Owen and G A WilliamsldquoInfrared spectrum and rotational isomerism of acrylic acidrdquoJournal of Molecular Structure vol 157 no 1ndash3 pp 17ndash25 1987

[18] K Bolton N L Owen and J Sheridan ldquoMicrowave spectra ofrotational isomers of acrylic acidrdquoNature vol 218 no 5138 pp266ndash267 1968

[19] G Williams N L Owen and J Sheridan ldquoSpectroscopicstudies of some substitutedmethyl formatesmdashpart 1microwavespectra and internal rotation barriers of methyl-fluoroformate-propiolate -cyanoformate -acrylate and -acetaterdquo Transac-tions of the Faraday Society vol 67 pp 922ndash949 1971

[20] T Tsuji H Ito H Takeuchi and S Konaka ldquoMolecularstructure and conformation ofmethylmethacrylate determinedby gas electron diffractionrdquo Journal of Molecular Structure vol475 no 1 pp 55ndash63 1999

[21] T Egawa S Maekawa H Fujiwara Takeuchi H Takeuchi andS Konaka ldquoMolecular structure and conformation of methylacrylate a gas electron diffraction study augmented by ab initiocalculation and rotational constantsrdquo Molecular Structure andSpectroscopy vol 352 pp 193ndash201 1995

[22] A Virdi V P Gupta and A Sharma ldquoAb initio studies onconformation vibrational and electronic spectra of methylmethacrylaterdquo Journal ofMolecular Structure vol 634 no 5 pp53ndash65 2003

[23] B L Baker M Orgill N L Owen et al ldquoThe molecularconformation of methyl methacrylatemdashan infrared and abinitio studyrdquo Journal of Molecular Structure vol 356 no 2 pp95ndash104 1995

[24] A N Mitra and I Santhanan ldquoRelativistic qqq spectra fromBethe-Salpeter premisesrdquo Physics Letters B vol 104 no 1 pp62ndash66 1981

[25] K Fan and J E Boggs ldquoRotational isomerism of acrylic acidrdquoJournal of Molecular Structure vol 157 no 1ndash3 pp 31ndash41 1987

[26] P Carmona and J Moreno ldquoThe infrared spectra and structureof methyl acrylaterdquo Journal of Molecular Structure vol 82 no3-4 pp 177ndash185 1982

[27] R J Loncharich T R Schwartz and K N Houk ldquoTheoreticalstudies of conformations of acrolein acrylic acid methyl acry-late and their Lewis acid complexesrdquo Journal of the AmericanChemical Society vol 109 no 1 pp 14ndash23 1987

[28] M Dulce G Faria J J C Teixeira-Dias and R FaustoldquoVibrational spectra and structure of methyl trans-crotonaterdquoVibrational Spectroscopy vol 2 no 2-3 pp 43ndash60 1991

[29] J J C Teixeira-Dias and R Fausto ldquoMolecular structure ofmethyl acrylate the high energy s-trans-(CO) conformerrdquoJournal of Molecular Structure vol 282 no 1-2 pp 123ndash1291993

[30] A J Bowles W O George and D B Cunliffe-Jones ldquoConfor-mations of some120572120573-unsaturated carbonyl compoundsmdashpart IIinfrared and Raman spectra of methyl and ethyl acrylates andtranscrotonatesrdquo Journal of the Chemical Society B pp 1070ndash1075 1970

[31] A D Becke ldquoDensity-functional thermochemistry IIIThe roleof exact exchangerdquoThe Journal of Chemical Physics vol 98 no7 pp 5648ndash5652 1993

[32] C Lee W Yang and R G Parr ldquoDevelopment of the Colle-Salvetti correlation-energy formula into a functional of theelectron densityrdquo Physical Review B vol 37 no 2 pp 785ndash7891988

[33] H Yoshida K Takeda J Okamura A Ehara and H MatsuuraldquoA new approach to vibrational analysis of large molecules bydensity functional theory wavenumber-linear scalingmethodrdquoJournal of Physical Chemistry A vol 106 no 14 pp 3580ndash35862002

14 Organic Chemistry International

[34] H Yoshida A Ehara and H Matsuura ldquoDensity functionalvibrational analysis using wavenumber-linear scale factorsrdquoChemical Physics Letters vol 325 no 4 pp 477ndash483 2000

[35] M J Frisch G W Trucks H B Schlegel et al Gaussian 03Revision B 01 Gaussian Pittsburgh Pa USA 2003

[36] J M L Martin and C Van Alsenoy GAR2PED A Program toObtain a Potential Energy Distribution from a Gaussian ArchiveRecord University of Antwerp 2009

[37] P Pulay G Fogarasi F Pang and J E Boggs ldquoSystematicab initio gradient calculation of molecular geometries forceconstants and dipole moment derivativesrdquo Journal of theAmerican Chemical Society vol 101 no 10 pp 2550ndash2560 1979

[38] S Mishra D Chaturvedi N Kumar P Tandon and H WSiesler ldquoAn ab initio and DFT study of structure and vibrationalspectra of 120574 form of Oleic acid comparison to experimentaldatardquo Chemistry and Physics of Lipids vol 163 no 2 pp 207ndash217 2010

[39] W O George D V Hassid and W F Maddams ldquoConfor-mations of some 120572120573-unsaturated carbonyl compoundsmdashpartIII infrared solution spectra of methyl [2H3]methyl ethyland [2H5]ethyl acrylates and trans-crotonatesrdquo Journal of theChemical Society Perkin Transactions 2 no 4 pp 400ndash4041972

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

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Medicinal ChemistryInternational Journal of

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CatalystsJournal of

Page 8: Research Article Molecular Structure and Vibrational Spectra ...e molecular geometry, vibrational frequencies, and infrared intensities have been calculated by using density functional

8 Organic Chemistry International

Table 2 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

83 mdash 30419158 291755246 160910 ] (C27H2) (38) ] (C9H2) (20) ] (C14H2) (19) ] (C21H2)(6) ] (C24H) (6)

84 mdash 30431697 29186929 145616 ] (C27H2) (47) ] (C9H2) (26) ] (C24H2) (10) ] (C14H2)(7)

85 mdash 3062906 293663657 465673 ] (C21H2) (55) ] (C27H2) (25) ] (C24H2) (9) ] (C12H13)(5)

86 2931 30788255 295110087 858987 ] (C27H2) (62) ] (C27H30) (10) ] 295503236 (C30H3)(9) ] (C9H2) (6) ] (C17H19) (6)

87 mdash 30831541 295503236 455349 ] (C30H31) (99)

88 mdash 30845244 295627682 351235 ] (C17H19) (67) ] (C17C19) (67) ] (C17C18) (17) ](C30H31) (15)

89 mdash 30879105 29593517 195239 ] (C9H2) (63) ] (O8C9) (16) ]-(C12H13) (11) ] (C17C19)(6)

90 2961 30931423 296410191 561433 ] (C17H19) (38) ] (C9H2) (26) ] (C17H20) (12) ](C14H2) (10) ] (C17H18) (9)

91 3038 31428663 300920422 51952 ] (C1C4) (45) ] (C1H2) (38) ] (C1H3) (9)92 mdash 3185092 304744188 32650 ] (C1H2) (95)93 3104 32359105 309338372 23617 ] (C4H5) (67) ] (C1H2) (22) ] (C1H3) (6)aAssignments and potential energy distribution (PED) (contributing ge 5) for vibrational normal mode Types of vibration ] stretching 120575 deformation oout-of-plane bending 120596 wagging y twisting 120588 rocking 120591 torsion w weak m medium sh shoulderbNormal mode number

1655 cmminus1 for s-cis conformer (Figure 3(b)) and 1647 cmminus1 forthe s-trans conformer (Figure 3(c)) The band at 1637 cmminus1may be used to definitely indicate that conformer with s-transarrangement of acrylic moiety is present or not in the liquid2-ethylhexyl acrylate

In the region from 1500 to 1200 cmminus1 in the experimen-tal spectrum (Figure 3) there are four bands of mediumintensity located at 1464 1408 1295 and 1272 cmminus1 Thebands of weak intensity of account of three are locatedat 1381 1357 and 1340 cmminus1 The calculated frequencies inthis region for the s-cis and s-trans conformations haveclose energies for each normal mode and the differencesdo not exceed 5 cmminus1 Based on the assignments reportedby Dulce et al [28] and our PED calculations we haveascribed the theoretical frequencies 1485 cmminus1 (s-cis) and1484 cmminus1 (s-trans) to the experimental band at 1464 cmminus1and they are representing a C

17H3symmetric bending The

calculated frequencies at 1479 1478 and 1476 cmminus1 may becontributed to the experimental band at 1464 cmminus1 due toits relatively large middle width of about 75 cmminus1 Mishra etal [38] have reported the experimental and the theoreticalIR spectra of 120574 form of oleic acid many peaks reported inthe region 1370 to 1220 cmminus1 for the CH

2carboxyl-sided

chain correspond approximately to those we found in ourspectrum from 1400 to 1200 cmminus1 and all of them may beassigned to CH

2deformation The assignment is based on

the bands intensities we found a good correlation betweenthe experimental and the theoretical spectra One shouldpoint out that the very intense bands predicted at 1267 and

1264 cmminus1 for s-trans form reproduce well the asymmetricshape of the experimental band at 1272 cmminus1 For bandsassignment see Tables 2 and 3

53 The CO Stretching and CH Bending Vibrations (1200ndash700 cmminus1 Figure 4) In this region in the IR spectrum thereis one very strong band at 1192 cmminus1 with weak shoulder at1160 cmminus1 and four medium intensity bands 1057 984 962shoulder at 933 and 811 cmminus1 The bands at 1116 1025 909896 852 770 and 727 cmminus1 (shoulder at 748 cmminus1) are ofweak intensity (Figure 4) Based on PEDs and intensities ofthe calculated frequencies we correlate the two intense bandsat 1192 and 1156 cmminus1 for the more stable and the less stableconformers to the band at 1191 cmminus1 in the experimentalIR spectrum The medium bands in IR spectrum are wellreproduced by the calculated peaks at 1079 999 976 941 and811 cmminus1 for the s-cis conformer and 1067 993 940 911 and828 cmminus1 for the s-trans conformer They may be ascribed toCH2rocking C

1H2wagging CCH rocking O

8C9 and C

1H2

twisting The peaks predicted by DFT at 728 and 783 cmminus1 ins-cis form and the peaks at 726 and 782 cmminus1 in the s-transformmay be correlated to the bands at 727 and 770 cmminus1 andthey are assigned to the CH

2deformations of the alkyl sides

of the title moleculeIn the IR spectra of 2-ethylhexyl acrylate reported in

this work there are a few bands with weak to very weakintensity which do not appear in the IR spectra of methylacrylate reported by Dulce et al [28] and George et al [39]These bands appear at 1157 1120 1052 and 1022 cmminus1 and they

Organic Chemistry International 9

Table 3 Frequencies and PEDs of s-trans 2-ethylhexyl acrylate

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

1 mdash 295569 2979981 13888 120591 (C21C24) (95)2 mdash 312922 3154848 12915 120591 (C21C24) (100)3 mdash 453002 4566086 00227 120591 (C21C24) (91) 120591 (O8C9) (6)4 mdash 69075 6959818 00113 120591 (C21C24) (98)5 mdash 916561 9231657 07304 120588 (C14H2) (64) 120591 (C9C12) (19) 120591 (C24C21) (15)6 mdash 106795 10753821 00788 120591 (C12C14) (92)7 mdash 116406 11719786 04606 120591 (O8C9) (90) 120591 (C21C24) (7)8 mdash 128002 12884855 07652 120591 (C21C24) (99)9 mdash 1377311 13862015 00737 120591 (C24C21) (94)10 mdash 1886176 18967867 24795 120591 (C24C21) (53) O (O8C9) (44)11 mdash 1964898 19756995 22280 120588 (C9H2) (82) 120591 (C9C12) (13)12 mdash 2346 23574391 17535 120588 (C30H3) (90) 120591 (C21C24) (7)13 mdash 2495865 25074252 32507 120588 (C30H3) (78) 120591 (C12C21) (19)14 mdash 2623636 26352416 12259 120588 (C9H2) (72) 120588 (C17H3) (22)15 mdash 2741636 27532362 05126 120591 (C12C21) (96)16 mdash 3352283 33631302 04554 120575 (C21C12C14) (93)17 mdash 3546136 355649 01655 120575 (C21C12C24) (95)18 mdash 406411 40725451 25402 120575 (C9C12C14) (92)19 mdash 4713032 47178287 10320 120588 (C9C12C14) (70) 120575 (C9C12C21) (12) 120588 (C14H2) (11)20 mdash 5098943 51009251 04733 y (C1H2) (86) O (C6O8) (12)

21 mdash 5140157 51418098 73067 120588 (C12C14C17) (38) 120588 (C9C12C21) (15) 120588 (C12C21) (14)120588 (C14C12H13) (13) 120588 (C1H2) (8) 120575 (C12C21C24) (7)

22 mdash 550859 55070531 22808 120588 (C9C12C14) (78) 120588 (C6O8C9) (9) 120588 (C1H2) (6)23 mdash 6360175 6349572 19146 120588 (O8C9C12) (97)24 727 (m) 7284338 72612214 43677 120588 (C9C12C21) (92)25 mdash 778027 77492902 06843 120588 (C9C12C21) (98)26 770 (m) 785397 78217532 18732 120588 (C21H2) (59) 120588 (C14H2) (36)27 811 (m) 8321364 82808904 215147 y (C1H2) (94) 120588 (C9H2) (5)

28 852 (w) 8501904 84580503 34731 120588 (C9C12C21) (47) 120588 (C9H2) (27) 120588 (C1H2) (15) ](C14C17) (5)

29 896 (w) 9017561 8963468 09206 120588 (C9C12C21) (73) 120588 (C21C24C27) (14)30 909 (w) 9065632 90105403 13451 120588 (C9C12C21) (46) 120588 (C9H2) (35) 120588 (C12C14C17) (9)31 933 (sh) 9170283 91129911 76343 120588 (O7C6O8) (86) 120588 (C9H2) (10)32 962 (m) 9470255 94064585 60649 120588 (C6O8C9) (99)33 mdash 9726775 96571834 70484 120588 (C6O8C9) (99)

34 984 (m) 10012212 99359199 344957 120596 (C1H2) (52) ] (C1C4) (15) 120575 (C4C6O8) (15) ] (C12C21)(15)

35 1015 (sh) 10171676 100915249 70006 ] (C12C21) (92)36 mdash 10219635 101383071 35045 ] (C21C24) (85) 120575 (C9C12O14) (9)37 1025 (sh) 10299052 102157589 185130 y (C1H2) (97)38 mdash 1040755 103215388 03554 ] (C21C24) (70) ] (C9C12) (14) y (C21H2) (5)39 mdash 10608287 105171458 55936 y (C21H2) (58) 120588 (C14C12H13) (29) 120588 (C14H2) (7)40 mdash 10640573 105485945 188097 ] (C21C24) (88) ] (C14C17) (8)41 1057 (m) 10767989 106726727 1926571 ] (C9O8) (82) ] (C14C17) (13)42 1060 (sh) 10895069 10796371 46500 120588 (C9H2) (40) 120575 (C9C12C21) (30) 120596 (C27H2) (25)43 1116 (w) 11506075 113903825 14631 120588 (C9C12H13) (51) 120575 (C9C12C21) (42)44 1191 11682621 115617915 32253 120588 (C14C12H13) (72) 120596 (C21H2) (16) 120588 (O8C9C12) (9)45 mdash 11850265 117244634 01695 120575 (C9C12C14) (94)

10 Organic Chemistry International

Table 3 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

46 mdash 1242923 122855525 17298 y (C21H2) (89)47 mdash 1258238 124337912 11546 120588 (C9C12C21) (35) 120596 (C21H2) (35) 120596 (C9H2) (27)48 mdash 12801017 126452842 779146 120596 (C21H2) (47) 120588 (C9C12C21) (37) 120588 (C9H2) (27)49 1272 1283202 126752616 3516365 120596 (C21H2) (60) y (C14H2) (27) y (C9H2) (10)50 mdash 12991286 128292094 44292 y (C9H2) (72) y (C21H2) (26)51 1295 13117811 129514505 72842 y (C14H2) (99)52 mdash 131875 130187577 68204 y (C14H2) (100)53 mdash 13264691 13093292 01479 y (C21H2) (97)54 mdash 13362199 131874163 04090 y (C24H2) (94) y (C21H2) (5)55 1340 1359997 134168063 10793 120596 (C21H2) (86) 120588 (C21C12C14) (7) 120596 (C9H2) (5)56 mdash 13800145 136097825 04801 120588 (C9C12C21) (43) 120575 (C9H12) (28) 120596 (C21H2) (25)

57 1357 13931134 137359902 28872 120596 (C9H2) (50) 120596 (C14H2) (23) 120575 (C21C12H13) (12) 120596(C21H2) (86)

58 mdash 14043849 138445461 09476 120596 (C21H2) (86) 120596 (C9H2) (12)59 mdash 14119509 139173911 08054 120596 (C9H2) (85) 120596 (C21H2) (14)60 1381 14145333 1394225 50233 120596 (C21H2) (54) 120596 (C9H2) (45)61 mdash 14173104 139689807 08100 120596 (C21H2) (89) 120596 (C9H2) (8)62 1408 14414398 142011302 305726 120596 (C9H2) (93) 120596 (C21H2) (5)

63 mdash 14831028 146015241 20326 120575 (C9H2) (38) 120575 (C21C12H13) (18) 120575 (C24C21C12) (15) 120575(C14H2) (13) 120575 (C24H2) (7) 120575 (C21H2) (6)

64 mdash 14876468 146451591 04300 120575 (C21C12H13) (33) 120575 (C27H2) (28) 120575 (C24H2) (20) 120575(C21H2) (10)

65 mdash 14916884 14683964 12432 120575 (C21H2) (54) 120575 (C9H2) (21) 120575 (C27H2) (11)

66 mdash 15000764 147644833 24692 120575 (C24H2) (32) 120575 (C21C12H13) (24) 120575 (C27H2) (8) 120575(C30H3) (8) 120575 (C21H2) (6)

67 mdash 1500718 147706413 70795 120575 (C30H3) (75) 120575 (C9H2) (11) 120575 (C27H2) (6)68 mdash 15025266 147879993 89950 120575 (C9H2) (74) 120575 (C17H3) (21)

69 1464 15081671 148421269 98400 120575 (C27H2) (26) 120575 (C30H3) (22) 120575 (C21H2) (14) 120575(C17H3) (14) 120575 (C24H2) (11)

70 mdash 15116225 148752807 105533 120575 (C21H2) (73) 120575 (C21C12H13) (6) 120575 (C24H2) (5) 120575(C17H3) (5)

71 mdash 1514069 14898752 56625 120575 (C24H2) (30) 120575 (C21H2) (29) 120575 (C21C24C27) (20) 120575(C27H2) (9)

72 1619 16787098 164738009 287096 ] (C1C4) (52) ] (C4C6) (22) 120575 (C9C12H13) (11) 120575(C21H2) (8)

73 1727 17668533 173134006 3155882 120575 (C9C12C21) (63) ] (C4C6) (16) 120575 (C21H2) (6) ](C6O7) (6)

74 mdash 2995932 287569419 20873 ] (C24H2) (35) ] (C14H2) (34) ] (C21H2) (25)

75 mdash 2998467 287800355 06759 ] (C24H2) (40) ] (C12H13) (29) ] (C21H2) (12) ](C14H2) (10)

76 mdash 3001649 288090203 135187 ] (C21H2) (92)77 mdash 30053152 288424116 132101 ] (C24H2) (87) ] (C24H2) (8)78 2861 3013385 289158948 585964 ] (C21H2) (45) ] (C30C32) (36) ] (C12H13) (12)79 2875 30178939 289569433 472871 ] (C30C32) (96)80 mdash 30236248 290091073 211397 ] (C14H12) (46) ] (C17H19) (32) ] (C17H18) (17)

81 mdash 30260401 290310887 159088 ] (C12H13) (30) ] (C17H19) (27) ] (C17H18) (13) ](C30C32) (12)

82 mdash 303455 291085214 329164 ] (C21H2) (66) ] (C14H2) (28)83 mdash 30404085 291618149 40314 ] (C21H2) (55) ] (C30H32) (27) ] (C12H13) (7)84 mdash 30437899 291925696 263738 ] (C21H2) (98)85 mdash 30609167 293482854 503404 ] (C21H2) (85) ] (C30C32) (12)86 2931 30786333 295092629 824131 ] (C30C32) (95)

Organic Chemistry International 11

Table 3 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

87 mdash 30833975 295525341 441245 ] (C30C32) (93)88 mdash 30842781 295605315 369537 ] (C17H19) (67) ] (C17H18) (18) ] (C21H2) (9)

89 mdash 30889498 296029541 151201 ] (C21H2) (52) ] (C9H2) (14) ] (C12H13) (14) ] (C14H2)(8) ] (C17H19) (7)

90 2961 30930704 296403663 595099 ] (C17H19) (36) ] (C14H2) (28) ] (C17H20) (10) ](C21H2) (10) ] (C17H18) (8) ] (C9H2) (6)

91 3038 31462567 301227655 52018 ] (C1C4) (50) ] (C1H2) (31) ] (C1H3) (10)92 3069 31857999 304808243 34136 ] (C4H5) (57) ] (C4C6) (23) ] (C1C4) (14)93 3104 3237707 309500628 44771 ] (C1H2) (70) ] (C1H3) (11) ] (C4H5) (7)aAssignments and potential energy distribution (PED) (contributing ge 5) for vibrational normal mode Types of vibration ] stretching 120575 deformation oout-of-plane bending 120596 wagging y twisting 120588 rocking 120591 torsion w weak m medium sh shoulderbNormal mode number

Abso

rban

ce

Wavenumbers (cmminus1)

121

08060402

01200 1300 1400 1500 1600 1700 1800

17721295

13401357

1381

14081464

1619 1637 1686

1727

(a)

IR in

tens

ity (k

mm

ol) 50

40

30

20

10

0

Wavenumbers (cmminus1)1200 1250 1300 1350 1400 1450 1500 1550 1600 1650 1700 1750 1800

1244 12841301

1311

1307

134113731390

1394

1417

14631476

14841491

1656

1735

(b)

IR in

tens

ity (k

mm

ol) 50

40

30

20

10

0

Wavenumbers (cmminus1)

1227

1264

12421284

1266

12941302

13411373 1393

1419

14601476

14871489

16461731

1200 1250 1300 1350 1400 1450 1500 1550 1600 1650 1700 1750 1800

(c)

Figure 3 Comparison of the experimental IR (a) C=O and C=C stretching and CH bending region (1800ndash1200 cmminus1) with the appropriatetheoretical B3LYP6-311+Glowastlowast spectra ((b) and (c)) for s-cis and s-trans 2-ethylhexyl acrylate respectively

are well correlated to the calculated peaks in DFT for bothconformers see Tables 2 and 3

The shoulders in the infrared spectrum at 1025 1015 cmminus1of weak to medium intensities may be correlated to the bands1037 1015 cmminus1 for s-cis and 1015 988 cmminus1 for the s-trans

conformer These bands are ascribed to the CH out-of-planebending modes of the vinyl group

The remaining bands of weak intensity in the experimen-tal IR spectrum are 909 896 and 852 cmminus1 These bandsare close to the ones at 911 996 and 847 cmminus1 for the s-cis

12 Organic Chemistry International

121

08060402

0700 800 900 1000 1100 1200

727 770

811

952 869909 933

962 9841015 1025

1057

11161060

1191

Abso

rban

ce

Wavenumbers (cmminus1)

(a)

20

10

0

728776 783

825

848895

900911 940 975

1000

10131037

1008 1152 11581180

1016

1139

1156

1191

700 800 900 1000 1100 1200Wavenumbers (cmminus1)

IR in

tens

ity (k

mm

ol)

(b)

725

775783

827

846 896

900

940 965

993

1009

10131021

1066

10331051

1054

1079 11381156

1171

700 800 900 1000 1100 1200Wavenumbers (cmminus1)

20

10

0IR in

tens

ity (k

mm

ol)

(c)

Figure 4 Comparison of the experimental IR (a) CO stretching and CH bending region (1200ndash700 cmminus1) with the appropriate theoreticalB3LYP6-311+Glowastlowast spectra ((b) and (c)) for s-cis and s-trans 2-ethylhexyl acrylate respectively

conformation of the titlemolecule All the vibrational normalmodes in this region are not pure and the majority of themwere ascribed according to PED calculations to CH bending(for more details see Tables 2 and 3)

54 Region below 700 cmminus1 This spectral region includesthe bands associated with C=CndashC CndashOndashC O=CndashO OndashCndashC CndashCndashC and CndashCndashC bending and torsion modes aboutthe single bonds OndashC and CndashC The frequencies and PEDcalculations are presented in Tables 2 and 3 Comparing the23 first normal modes for the two conformers we notice thatthey have the same type of vibrational modes However thenormal modes 16 17 and 18 represent CCC bending in the s-trans andCHandCCC rockingmodes in the s-cis conformer

Due to the lack of experimental data on this region wecompare our calculated frequencies to some experimental IRbands of related molecules presented in the literature Thebands at 356 254 116 and 100 cmminus1 are close to the bandsat 349(A1015840) 244(A10158401015840) 114(A10158401015840) and 114 cmminus1 (A10158401015840) reported byDulce et al [28] From the same work the bands at 530 244114 and 114 cmminus1 belonging to A10158401015840 symmetry for the s-trans

methyl acrylate in liquid state are close to our calculatedbands in DFT at 542 244 116 and 106 cmminus1

6 Conclusions

Themid-IR spectrum of 2-ethylhexyl acrylate was measuredand interpreted with support of the DFTB3LYP6-311+Glowastlowastcalculated vibrational spectra followed by potential energydistribution analysis Assuming the s-cis and s-trans confor-mations we found two stable conformations close in theirenergies The fully optimized geometries of s-cis and s-transconformations by DFTB3LYP6-311+Glowastlowast were comparedwith the experimental and theoretical data presented in theliterature on the methyl acrylate molecule The compari-son shows a good agreement The experimental vibrationalspectrum is in good agreement with the theoretical spectracalculated for the two conformations Two neighbor bandsin the IR spectrum at 1619 and 1637 cmminus1 may be used ascharacteristic bands to locate and distinguish the existence ofone or both conformations

Organic Chemistry International 13

References

[1] M Salkind E H Riddle and R W Keefer ldquoAcrylates andmethacrylates ester manufacture and marketsrdquo Industrial ampEngineering Chemistry Research vol 51 no 11 pp 1328ndash13341959

[2] K S Anseth S M Newman and C N Bowman ldquoPolymericdental composites properties and reaction behavior of multi-methacrylate dental restorationsrdquo Advances in Polymer Sciencevol 122 pp 176ndash217 1995

[3] J G Kloosterboer ldquoNetwork formation by chain crosslink-ing photopolymerization and its application in electronicsrdquoAdvances in Polymer Science vol 84 pp 1ndash61 1988

[4] K Matyjaszewski Y Gnanou and L Leibler MacromolecularEngineering vol 1 Wiley-VCH Weinheim Germany 2007

[5] M Orgill B L Baker and N L Owen ldquoFTIR studies ofconformational isomerism in acrylates and acrylic acidsrdquo Spec-trochimica Acta A vol 55 no 5 pp 1021ndash1024 1999

[6] M Salkind ldquoReaches into the marketrdquo Industrial amp EngineeringChemistry Research vol 56 pp 62ndash110 1964

[7] E Takacs K Dajka and L Wojnarovits ldquoStudy of high-energyradiation initiated polymerization of butyl acrylaterdquo RadiationPhysics and Chemistry vol 63 no 1 pp 41ndash44 2002

[8] H Yu J Peng M Zhai J Li G Wei and J Qiao ldquoRadiation-induced copolymerization of styrenen-butyl acrylate in thepresence of ultra-fine powdered styrene-butadiene rubberrdquoRadiation Physics and Chemistry vol 76 no 11-12 pp 1736ndash1740 2007

[9] P F Canamero J Luis de la Fuente and M Fermandez-GarcıaldquoCuring kinetic study using a well-controlled multifunctionalcopolymer based on glycidyl methacrylaterdquo European PolymerJournal vol 45 no 9 pp 2665ndash2673 2009

[10] DMathew C P ReghunadhanNair and K N Ninan ldquoPendantcyanate functional vinyl polymers and imidophenolic-triazinesthereof synthesis and thermal propertiesrdquo European PolymerJournal vol 36 no 6 pp 1195ndash1208 2000

[11] S Mitra S Chattopadhyay S Sabharwal and A K BhowmickldquoElectron beam crosslinked gels-Preparation characterizationand their effect on the mechanical dynamic mechanical andrheological properties of rubbersrdquoRadiation Physics and Chem-istry vol 79 no 2 pp 289ndash296 2010

[12] P Canamero-Martınez M Fermandez-Garcıa and J Luis de laFuente ldquoRheological cure characterization of a polyfunctionalepoxy acrylic resinrdquo Reactive and Functional Polymers vol 70no 10 pp 761ndash766 2010

[13] F Chu T McKenna and S Lu ldquoCuring kinetics of an acrylicresinepoxy resin system using dynamic scanning calorimetryrdquoEuropean Polymer Journal vol 33 no 6 pp 837ndash840 1997

[14] M C Douskey M S Gebhard A V McCormick et alldquoSpectroscopic studies of a novel cyclic oligomer with pendantalkoxysilane groupsrdquo Progress in Organic Coatings vol 45 no2-3 pp 145ndash157 2002

[15] R J Day P A Lovell and A A Wazzan ldquoToughened car-bonepoxy composites made by using coreshell particlesrdquoComposites Science andTechnology vol 61 no 1 pp 41ndash56 2001

[16] K Bolton D G Lister and J Sheridan ldquoRotational isomerismbarrier to internal rotation and electric dipole moment ofacrylic acid bymicrowave spectroscopyrdquo Journal of the ChemicalSociety Faraday Transactions 2 vol 70 pp 113ndash123 1974

[17] S W Charles F C Cullen N L Owen and G A WilliamsldquoInfrared spectrum and rotational isomerism of acrylic acidrdquoJournal of Molecular Structure vol 157 no 1ndash3 pp 17ndash25 1987

[18] K Bolton N L Owen and J Sheridan ldquoMicrowave spectra ofrotational isomers of acrylic acidrdquoNature vol 218 no 5138 pp266ndash267 1968

[19] G Williams N L Owen and J Sheridan ldquoSpectroscopicstudies of some substitutedmethyl formatesmdashpart 1microwavespectra and internal rotation barriers of methyl-fluoroformate-propiolate -cyanoformate -acrylate and -acetaterdquo Transac-tions of the Faraday Society vol 67 pp 922ndash949 1971

[20] T Tsuji H Ito H Takeuchi and S Konaka ldquoMolecularstructure and conformation ofmethylmethacrylate determinedby gas electron diffractionrdquo Journal of Molecular Structure vol475 no 1 pp 55ndash63 1999

[21] T Egawa S Maekawa H Fujiwara Takeuchi H Takeuchi andS Konaka ldquoMolecular structure and conformation of methylacrylate a gas electron diffraction study augmented by ab initiocalculation and rotational constantsrdquo Molecular Structure andSpectroscopy vol 352 pp 193ndash201 1995

[22] A Virdi V P Gupta and A Sharma ldquoAb initio studies onconformation vibrational and electronic spectra of methylmethacrylaterdquo Journal ofMolecular Structure vol 634 no 5 pp53ndash65 2003

[23] B L Baker M Orgill N L Owen et al ldquoThe molecularconformation of methyl methacrylatemdashan infrared and abinitio studyrdquo Journal of Molecular Structure vol 356 no 2 pp95ndash104 1995

[24] A N Mitra and I Santhanan ldquoRelativistic qqq spectra fromBethe-Salpeter premisesrdquo Physics Letters B vol 104 no 1 pp62ndash66 1981

[25] K Fan and J E Boggs ldquoRotational isomerism of acrylic acidrdquoJournal of Molecular Structure vol 157 no 1ndash3 pp 31ndash41 1987

[26] P Carmona and J Moreno ldquoThe infrared spectra and structureof methyl acrylaterdquo Journal of Molecular Structure vol 82 no3-4 pp 177ndash185 1982

[27] R J Loncharich T R Schwartz and K N Houk ldquoTheoreticalstudies of conformations of acrolein acrylic acid methyl acry-late and their Lewis acid complexesrdquo Journal of the AmericanChemical Society vol 109 no 1 pp 14ndash23 1987

[28] M Dulce G Faria J J C Teixeira-Dias and R FaustoldquoVibrational spectra and structure of methyl trans-crotonaterdquoVibrational Spectroscopy vol 2 no 2-3 pp 43ndash60 1991

[29] J J C Teixeira-Dias and R Fausto ldquoMolecular structure ofmethyl acrylate the high energy s-trans-(CO) conformerrdquoJournal of Molecular Structure vol 282 no 1-2 pp 123ndash1291993

[30] A J Bowles W O George and D B Cunliffe-Jones ldquoConfor-mations of some120572120573-unsaturated carbonyl compoundsmdashpart IIinfrared and Raman spectra of methyl and ethyl acrylates andtranscrotonatesrdquo Journal of the Chemical Society B pp 1070ndash1075 1970

[31] A D Becke ldquoDensity-functional thermochemistry IIIThe roleof exact exchangerdquoThe Journal of Chemical Physics vol 98 no7 pp 5648ndash5652 1993

[32] C Lee W Yang and R G Parr ldquoDevelopment of the Colle-Salvetti correlation-energy formula into a functional of theelectron densityrdquo Physical Review B vol 37 no 2 pp 785ndash7891988

[33] H Yoshida K Takeda J Okamura A Ehara and H MatsuuraldquoA new approach to vibrational analysis of large molecules bydensity functional theory wavenumber-linear scalingmethodrdquoJournal of Physical Chemistry A vol 106 no 14 pp 3580ndash35862002

14 Organic Chemistry International

[34] H Yoshida A Ehara and H Matsuura ldquoDensity functionalvibrational analysis using wavenumber-linear scale factorsrdquoChemical Physics Letters vol 325 no 4 pp 477ndash483 2000

[35] M J Frisch G W Trucks H B Schlegel et al Gaussian 03Revision B 01 Gaussian Pittsburgh Pa USA 2003

[36] J M L Martin and C Van Alsenoy GAR2PED A Program toObtain a Potential Energy Distribution from a Gaussian ArchiveRecord University of Antwerp 2009

[37] P Pulay G Fogarasi F Pang and J E Boggs ldquoSystematicab initio gradient calculation of molecular geometries forceconstants and dipole moment derivativesrdquo Journal of theAmerican Chemical Society vol 101 no 10 pp 2550ndash2560 1979

[38] S Mishra D Chaturvedi N Kumar P Tandon and H WSiesler ldquoAn ab initio and DFT study of structure and vibrationalspectra of 120574 form of Oleic acid comparison to experimentaldatardquo Chemistry and Physics of Lipids vol 163 no 2 pp 207ndash217 2010

[39] W O George D V Hassid and W F Maddams ldquoConfor-mations of some 120572120573-unsaturated carbonyl compoundsmdashpartIII infrared solution spectra of methyl [2H3]methyl ethyland [2H5]ethyl acrylates and trans-crotonatesrdquo Journal of theChemical Society Perkin Transactions 2 no 4 pp 400ndash4041972

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

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Carbohydrate Chemistry

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CatalystsJournal of

Page 9: Research Article Molecular Structure and Vibrational Spectra ...e molecular geometry, vibrational frequencies, and infrared intensities have been calculated by using density functional

Organic Chemistry International 9

Table 3 Frequencies and PEDs of s-trans 2-ethylhexyl acrylate

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

1 mdash 295569 2979981 13888 120591 (C21C24) (95)2 mdash 312922 3154848 12915 120591 (C21C24) (100)3 mdash 453002 4566086 00227 120591 (C21C24) (91) 120591 (O8C9) (6)4 mdash 69075 6959818 00113 120591 (C21C24) (98)5 mdash 916561 9231657 07304 120588 (C14H2) (64) 120591 (C9C12) (19) 120591 (C24C21) (15)6 mdash 106795 10753821 00788 120591 (C12C14) (92)7 mdash 116406 11719786 04606 120591 (O8C9) (90) 120591 (C21C24) (7)8 mdash 128002 12884855 07652 120591 (C21C24) (99)9 mdash 1377311 13862015 00737 120591 (C24C21) (94)10 mdash 1886176 18967867 24795 120591 (C24C21) (53) O (O8C9) (44)11 mdash 1964898 19756995 22280 120588 (C9H2) (82) 120591 (C9C12) (13)12 mdash 2346 23574391 17535 120588 (C30H3) (90) 120591 (C21C24) (7)13 mdash 2495865 25074252 32507 120588 (C30H3) (78) 120591 (C12C21) (19)14 mdash 2623636 26352416 12259 120588 (C9H2) (72) 120588 (C17H3) (22)15 mdash 2741636 27532362 05126 120591 (C12C21) (96)16 mdash 3352283 33631302 04554 120575 (C21C12C14) (93)17 mdash 3546136 355649 01655 120575 (C21C12C24) (95)18 mdash 406411 40725451 25402 120575 (C9C12C14) (92)19 mdash 4713032 47178287 10320 120588 (C9C12C14) (70) 120575 (C9C12C21) (12) 120588 (C14H2) (11)20 mdash 5098943 51009251 04733 y (C1H2) (86) O (C6O8) (12)

21 mdash 5140157 51418098 73067 120588 (C12C14C17) (38) 120588 (C9C12C21) (15) 120588 (C12C21) (14)120588 (C14C12H13) (13) 120588 (C1H2) (8) 120575 (C12C21C24) (7)

22 mdash 550859 55070531 22808 120588 (C9C12C14) (78) 120588 (C6O8C9) (9) 120588 (C1H2) (6)23 mdash 6360175 6349572 19146 120588 (O8C9C12) (97)24 727 (m) 7284338 72612214 43677 120588 (C9C12C21) (92)25 mdash 778027 77492902 06843 120588 (C9C12C21) (98)26 770 (m) 785397 78217532 18732 120588 (C21H2) (59) 120588 (C14H2) (36)27 811 (m) 8321364 82808904 215147 y (C1H2) (94) 120588 (C9H2) (5)

28 852 (w) 8501904 84580503 34731 120588 (C9C12C21) (47) 120588 (C9H2) (27) 120588 (C1H2) (15) ](C14C17) (5)

29 896 (w) 9017561 8963468 09206 120588 (C9C12C21) (73) 120588 (C21C24C27) (14)30 909 (w) 9065632 90105403 13451 120588 (C9C12C21) (46) 120588 (C9H2) (35) 120588 (C12C14C17) (9)31 933 (sh) 9170283 91129911 76343 120588 (O7C6O8) (86) 120588 (C9H2) (10)32 962 (m) 9470255 94064585 60649 120588 (C6O8C9) (99)33 mdash 9726775 96571834 70484 120588 (C6O8C9) (99)

34 984 (m) 10012212 99359199 344957 120596 (C1H2) (52) ] (C1C4) (15) 120575 (C4C6O8) (15) ] (C12C21)(15)

35 1015 (sh) 10171676 100915249 70006 ] (C12C21) (92)36 mdash 10219635 101383071 35045 ] (C21C24) (85) 120575 (C9C12O14) (9)37 1025 (sh) 10299052 102157589 185130 y (C1H2) (97)38 mdash 1040755 103215388 03554 ] (C21C24) (70) ] (C9C12) (14) y (C21H2) (5)39 mdash 10608287 105171458 55936 y (C21H2) (58) 120588 (C14C12H13) (29) 120588 (C14H2) (7)40 mdash 10640573 105485945 188097 ] (C21C24) (88) ] (C14C17) (8)41 1057 (m) 10767989 106726727 1926571 ] (C9O8) (82) ] (C14C17) (13)42 1060 (sh) 10895069 10796371 46500 120588 (C9H2) (40) 120575 (C9C12C21) (30) 120596 (C27H2) (25)43 1116 (w) 11506075 113903825 14631 120588 (C9C12H13) (51) 120575 (C9C12C21) (42)44 1191 11682621 115617915 32253 120588 (C14C12H13) (72) 120596 (C21H2) (16) 120588 (O8C9C12) (9)45 mdash 11850265 117244634 01695 120575 (C9C12C14) (94)

10 Organic Chemistry International

Table 3 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

46 mdash 1242923 122855525 17298 y (C21H2) (89)47 mdash 1258238 124337912 11546 120588 (C9C12C21) (35) 120596 (C21H2) (35) 120596 (C9H2) (27)48 mdash 12801017 126452842 779146 120596 (C21H2) (47) 120588 (C9C12C21) (37) 120588 (C9H2) (27)49 1272 1283202 126752616 3516365 120596 (C21H2) (60) y (C14H2) (27) y (C9H2) (10)50 mdash 12991286 128292094 44292 y (C9H2) (72) y (C21H2) (26)51 1295 13117811 129514505 72842 y (C14H2) (99)52 mdash 131875 130187577 68204 y (C14H2) (100)53 mdash 13264691 13093292 01479 y (C21H2) (97)54 mdash 13362199 131874163 04090 y (C24H2) (94) y (C21H2) (5)55 1340 1359997 134168063 10793 120596 (C21H2) (86) 120588 (C21C12C14) (7) 120596 (C9H2) (5)56 mdash 13800145 136097825 04801 120588 (C9C12C21) (43) 120575 (C9H12) (28) 120596 (C21H2) (25)

57 1357 13931134 137359902 28872 120596 (C9H2) (50) 120596 (C14H2) (23) 120575 (C21C12H13) (12) 120596(C21H2) (86)

58 mdash 14043849 138445461 09476 120596 (C21H2) (86) 120596 (C9H2) (12)59 mdash 14119509 139173911 08054 120596 (C9H2) (85) 120596 (C21H2) (14)60 1381 14145333 1394225 50233 120596 (C21H2) (54) 120596 (C9H2) (45)61 mdash 14173104 139689807 08100 120596 (C21H2) (89) 120596 (C9H2) (8)62 1408 14414398 142011302 305726 120596 (C9H2) (93) 120596 (C21H2) (5)

63 mdash 14831028 146015241 20326 120575 (C9H2) (38) 120575 (C21C12H13) (18) 120575 (C24C21C12) (15) 120575(C14H2) (13) 120575 (C24H2) (7) 120575 (C21H2) (6)

64 mdash 14876468 146451591 04300 120575 (C21C12H13) (33) 120575 (C27H2) (28) 120575 (C24H2) (20) 120575(C21H2) (10)

65 mdash 14916884 14683964 12432 120575 (C21H2) (54) 120575 (C9H2) (21) 120575 (C27H2) (11)

66 mdash 15000764 147644833 24692 120575 (C24H2) (32) 120575 (C21C12H13) (24) 120575 (C27H2) (8) 120575(C30H3) (8) 120575 (C21H2) (6)

67 mdash 1500718 147706413 70795 120575 (C30H3) (75) 120575 (C9H2) (11) 120575 (C27H2) (6)68 mdash 15025266 147879993 89950 120575 (C9H2) (74) 120575 (C17H3) (21)

69 1464 15081671 148421269 98400 120575 (C27H2) (26) 120575 (C30H3) (22) 120575 (C21H2) (14) 120575(C17H3) (14) 120575 (C24H2) (11)

70 mdash 15116225 148752807 105533 120575 (C21H2) (73) 120575 (C21C12H13) (6) 120575 (C24H2) (5) 120575(C17H3) (5)

71 mdash 1514069 14898752 56625 120575 (C24H2) (30) 120575 (C21H2) (29) 120575 (C21C24C27) (20) 120575(C27H2) (9)

72 1619 16787098 164738009 287096 ] (C1C4) (52) ] (C4C6) (22) 120575 (C9C12H13) (11) 120575(C21H2) (8)

73 1727 17668533 173134006 3155882 120575 (C9C12C21) (63) ] (C4C6) (16) 120575 (C21H2) (6) ](C6O7) (6)

74 mdash 2995932 287569419 20873 ] (C24H2) (35) ] (C14H2) (34) ] (C21H2) (25)

75 mdash 2998467 287800355 06759 ] (C24H2) (40) ] (C12H13) (29) ] (C21H2) (12) ](C14H2) (10)

76 mdash 3001649 288090203 135187 ] (C21H2) (92)77 mdash 30053152 288424116 132101 ] (C24H2) (87) ] (C24H2) (8)78 2861 3013385 289158948 585964 ] (C21H2) (45) ] (C30C32) (36) ] (C12H13) (12)79 2875 30178939 289569433 472871 ] (C30C32) (96)80 mdash 30236248 290091073 211397 ] (C14H12) (46) ] (C17H19) (32) ] (C17H18) (17)

81 mdash 30260401 290310887 159088 ] (C12H13) (30) ] (C17H19) (27) ] (C17H18) (13) ](C30C32) (12)

82 mdash 303455 291085214 329164 ] (C21H2) (66) ] (C14H2) (28)83 mdash 30404085 291618149 40314 ] (C21H2) (55) ] (C30H32) (27) ] (C12H13) (7)84 mdash 30437899 291925696 263738 ] (C21H2) (98)85 mdash 30609167 293482854 503404 ] (C21H2) (85) ] (C30C32) (12)86 2931 30786333 295092629 824131 ] (C30C32) (95)

Organic Chemistry International 11

Table 3 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

87 mdash 30833975 295525341 441245 ] (C30C32) (93)88 mdash 30842781 295605315 369537 ] (C17H19) (67) ] (C17H18) (18) ] (C21H2) (9)

89 mdash 30889498 296029541 151201 ] (C21H2) (52) ] (C9H2) (14) ] (C12H13) (14) ] (C14H2)(8) ] (C17H19) (7)

90 2961 30930704 296403663 595099 ] (C17H19) (36) ] (C14H2) (28) ] (C17H20) (10) ](C21H2) (10) ] (C17H18) (8) ] (C9H2) (6)

91 3038 31462567 301227655 52018 ] (C1C4) (50) ] (C1H2) (31) ] (C1H3) (10)92 3069 31857999 304808243 34136 ] (C4H5) (57) ] (C4C6) (23) ] (C1C4) (14)93 3104 3237707 309500628 44771 ] (C1H2) (70) ] (C1H3) (11) ] (C4H5) (7)aAssignments and potential energy distribution (PED) (contributing ge 5) for vibrational normal mode Types of vibration ] stretching 120575 deformation oout-of-plane bending 120596 wagging y twisting 120588 rocking 120591 torsion w weak m medium sh shoulderbNormal mode number

Abso

rban

ce

Wavenumbers (cmminus1)

121

08060402

01200 1300 1400 1500 1600 1700 1800

17721295

13401357

1381

14081464

1619 1637 1686

1727

(a)

IR in

tens

ity (k

mm

ol) 50

40

30

20

10

0

Wavenumbers (cmminus1)1200 1250 1300 1350 1400 1450 1500 1550 1600 1650 1700 1750 1800

1244 12841301

1311

1307

134113731390

1394

1417

14631476

14841491

1656

1735

(b)

IR in

tens

ity (k

mm

ol) 50

40

30

20

10

0

Wavenumbers (cmminus1)

1227

1264

12421284

1266

12941302

13411373 1393

1419

14601476

14871489

16461731

1200 1250 1300 1350 1400 1450 1500 1550 1600 1650 1700 1750 1800

(c)

Figure 3 Comparison of the experimental IR (a) C=O and C=C stretching and CH bending region (1800ndash1200 cmminus1) with the appropriatetheoretical B3LYP6-311+Glowastlowast spectra ((b) and (c)) for s-cis and s-trans 2-ethylhexyl acrylate respectively

are well correlated to the calculated peaks in DFT for bothconformers see Tables 2 and 3

The shoulders in the infrared spectrum at 1025 1015 cmminus1of weak to medium intensities may be correlated to the bands1037 1015 cmminus1 for s-cis and 1015 988 cmminus1 for the s-trans

conformer These bands are ascribed to the CH out-of-planebending modes of the vinyl group

The remaining bands of weak intensity in the experimen-tal IR spectrum are 909 896 and 852 cmminus1 These bandsare close to the ones at 911 996 and 847 cmminus1 for the s-cis

12 Organic Chemistry International

121

08060402

0700 800 900 1000 1100 1200

727 770

811

952 869909 933

962 9841015 1025

1057

11161060

1191

Abso

rban

ce

Wavenumbers (cmminus1)

(a)

20

10

0

728776 783

825

848895

900911 940 975

1000

10131037

1008 1152 11581180

1016

1139

1156

1191

700 800 900 1000 1100 1200Wavenumbers (cmminus1)

IR in

tens

ity (k

mm

ol)

(b)

725

775783

827

846 896

900

940 965

993

1009

10131021

1066

10331051

1054

1079 11381156

1171

700 800 900 1000 1100 1200Wavenumbers (cmminus1)

20

10

0IR in

tens

ity (k

mm

ol)

(c)

Figure 4 Comparison of the experimental IR (a) CO stretching and CH bending region (1200ndash700 cmminus1) with the appropriate theoreticalB3LYP6-311+Glowastlowast spectra ((b) and (c)) for s-cis and s-trans 2-ethylhexyl acrylate respectively

conformation of the titlemolecule All the vibrational normalmodes in this region are not pure and the majority of themwere ascribed according to PED calculations to CH bending(for more details see Tables 2 and 3)

54 Region below 700 cmminus1 This spectral region includesthe bands associated with C=CndashC CndashOndashC O=CndashO OndashCndashC CndashCndashC and CndashCndashC bending and torsion modes aboutthe single bonds OndashC and CndashC The frequencies and PEDcalculations are presented in Tables 2 and 3 Comparing the23 first normal modes for the two conformers we notice thatthey have the same type of vibrational modes However thenormal modes 16 17 and 18 represent CCC bending in the s-trans andCHandCCC rockingmodes in the s-cis conformer

Due to the lack of experimental data on this region wecompare our calculated frequencies to some experimental IRbands of related molecules presented in the literature Thebands at 356 254 116 and 100 cmminus1 are close to the bandsat 349(A1015840) 244(A10158401015840) 114(A10158401015840) and 114 cmminus1 (A10158401015840) reported byDulce et al [28] From the same work the bands at 530 244114 and 114 cmminus1 belonging to A10158401015840 symmetry for the s-trans

methyl acrylate in liquid state are close to our calculatedbands in DFT at 542 244 116 and 106 cmminus1

6 Conclusions

Themid-IR spectrum of 2-ethylhexyl acrylate was measuredand interpreted with support of the DFTB3LYP6-311+Glowastlowastcalculated vibrational spectra followed by potential energydistribution analysis Assuming the s-cis and s-trans confor-mations we found two stable conformations close in theirenergies The fully optimized geometries of s-cis and s-transconformations by DFTB3LYP6-311+Glowastlowast were comparedwith the experimental and theoretical data presented in theliterature on the methyl acrylate molecule The compari-son shows a good agreement The experimental vibrationalspectrum is in good agreement with the theoretical spectracalculated for the two conformations Two neighbor bandsin the IR spectrum at 1619 and 1637 cmminus1 may be used ascharacteristic bands to locate and distinguish the existence ofone or both conformations

Organic Chemistry International 13

References

[1] M Salkind E H Riddle and R W Keefer ldquoAcrylates andmethacrylates ester manufacture and marketsrdquo Industrial ampEngineering Chemistry Research vol 51 no 11 pp 1328ndash13341959

[2] K S Anseth S M Newman and C N Bowman ldquoPolymericdental composites properties and reaction behavior of multi-methacrylate dental restorationsrdquo Advances in Polymer Sciencevol 122 pp 176ndash217 1995

[3] J G Kloosterboer ldquoNetwork formation by chain crosslink-ing photopolymerization and its application in electronicsrdquoAdvances in Polymer Science vol 84 pp 1ndash61 1988

[4] K Matyjaszewski Y Gnanou and L Leibler MacromolecularEngineering vol 1 Wiley-VCH Weinheim Germany 2007

[5] M Orgill B L Baker and N L Owen ldquoFTIR studies ofconformational isomerism in acrylates and acrylic acidsrdquo Spec-trochimica Acta A vol 55 no 5 pp 1021ndash1024 1999

[6] M Salkind ldquoReaches into the marketrdquo Industrial amp EngineeringChemistry Research vol 56 pp 62ndash110 1964

[7] E Takacs K Dajka and L Wojnarovits ldquoStudy of high-energyradiation initiated polymerization of butyl acrylaterdquo RadiationPhysics and Chemistry vol 63 no 1 pp 41ndash44 2002

[8] H Yu J Peng M Zhai J Li G Wei and J Qiao ldquoRadiation-induced copolymerization of styrenen-butyl acrylate in thepresence of ultra-fine powdered styrene-butadiene rubberrdquoRadiation Physics and Chemistry vol 76 no 11-12 pp 1736ndash1740 2007

[9] P F Canamero J Luis de la Fuente and M Fermandez-GarcıaldquoCuring kinetic study using a well-controlled multifunctionalcopolymer based on glycidyl methacrylaterdquo European PolymerJournal vol 45 no 9 pp 2665ndash2673 2009

[10] DMathew C P ReghunadhanNair and K N Ninan ldquoPendantcyanate functional vinyl polymers and imidophenolic-triazinesthereof synthesis and thermal propertiesrdquo European PolymerJournal vol 36 no 6 pp 1195ndash1208 2000

[11] S Mitra S Chattopadhyay S Sabharwal and A K BhowmickldquoElectron beam crosslinked gels-Preparation characterizationand their effect on the mechanical dynamic mechanical andrheological properties of rubbersrdquoRadiation Physics and Chem-istry vol 79 no 2 pp 289ndash296 2010

[12] P Canamero-Martınez M Fermandez-Garcıa and J Luis de laFuente ldquoRheological cure characterization of a polyfunctionalepoxy acrylic resinrdquo Reactive and Functional Polymers vol 70no 10 pp 761ndash766 2010

[13] F Chu T McKenna and S Lu ldquoCuring kinetics of an acrylicresinepoxy resin system using dynamic scanning calorimetryrdquoEuropean Polymer Journal vol 33 no 6 pp 837ndash840 1997

[14] M C Douskey M S Gebhard A V McCormick et alldquoSpectroscopic studies of a novel cyclic oligomer with pendantalkoxysilane groupsrdquo Progress in Organic Coatings vol 45 no2-3 pp 145ndash157 2002

[15] R J Day P A Lovell and A A Wazzan ldquoToughened car-bonepoxy composites made by using coreshell particlesrdquoComposites Science andTechnology vol 61 no 1 pp 41ndash56 2001

[16] K Bolton D G Lister and J Sheridan ldquoRotational isomerismbarrier to internal rotation and electric dipole moment ofacrylic acid bymicrowave spectroscopyrdquo Journal of the ChemicalSociety Faraday Transactions 2 vol 70 pp 113ndash123 1974

[17] S W Charles F C Cullen N L Owen and G A WilliamsldquoInfrared spectrum and rotational isomerism of acrylic acidrdquoJournal of Molecular Structure vol 157 no 1ndash3 pp 17ndash25 1987

[18] K Bolton N L Owen and J Sheridan ldquoMicrowave spectra ofrotational isomers of acrylic acidrdquoNature vol 218 no 5138 pp266ndash267 1968

[19] G Williams N L Owen and J Sheridan ldquoSpectroscopicstudies of some substitutedmethyl formatesmdashpart 1microwavespectra and internal rotation barriers of methyl-fluoroformate-propiolate -cyanoformate -acrylate and -acetaterdquo Transac-tions of the Faraday Society vol 67 pp 922ndash949 1971

[20] T Tsuji H Ito H Takeuchi and S Konaka ldquoMolecularstructure and conformation ofmethylmethacrylate determinedby gas electron diffractionrdquo Journal of Molecular Structure vol475 no 1 pp 55ndash63 1999

[21] T Egawa S Maekawa H Fujiwara Takeuchi H Takeuchi andS Konaka ldquoMolecular structure and conformation of methylacrylate a gas electron diffraction study augmented by ab initiocalculation and rotational constantsrdquo Molecular Structure andSpectroscopy vol 352 pp 193ndash201 1995

[22] A Virdi V P Gupta and A Sharma ldquoAb initio studies onconformation vibrational and electronic spectra of methylmethacrylaterdquo Journal ofMolecular Structure vol 634 no 5 pp53ndash65 2003

[23] B L Baker M Orgill N L Owen et al ldquoThe molecularconformation of methyl methacrylatemdashan infrared and abinitio studyrdquo Journal of Molecular Structure vol 356 no 2 pp95ndash104 1995

[24] A N Mitra and I Santhanan ldquoRelativistic qqq spectra fromBethe-Salpeter premisesrdquo Physics Letters B vol 104 no 1 pp62ndash66 1981

[25] K Fan and J E Boggs ldquoRotational isomerism of acrylic acidrdquoJournal of Molecular Structure vol 157 no 1ndash3 pp 31ndash41 1987

[26] P Carmona and J Moreno ldquoThe infrared spectra and structureof methyl acrylaterdquo Journal of Molecular Structure vol 82 no3-4 pp 177ndash185 1982

[27] R J Loncharich T R Schwartz and K N Houk ldquoTheoreticalstudies of conformations of acrolein acrylic acid methyl acry-late and their Lewis acid complexesrdquo Journal of the AmericanChemical Society vol 109 no 1 pp 14ndash23 1987

[28] M Dulce G Faria J J C Teixeira-Dias and R FaustoldquoVibrational spectra and structure of methyl trans-crotonaterdquoVibrational Spectroscopy vol 2 no 2-3 pp 43ndash60 1991

[29] J J C Teixeira-Dias and R Fausto ldquoMolecular structure ofmethyl acrylate the high energy s-trans-(CO) conformerrdquoJournal of Molecular Structure vol 282 no 1-2 pp 123ndash1291993

[30] A J Bowles W O George and D B Cunliffe-Jones ldquoConfor-mations of some120572120573-unsaturated carbonyl compoundsmdashpart IIinfrared and Raman spectra of methyl and ethyl acrylates andtranscrotonatesrdquo Journal of the Chemical Society B pp 1070ndash1075 1970

[31] A D Becke ldquoDensity-functional thermochemistry IIIThe roleof exact exchangerdquoThe Journal of Chemical Physics vol 98 no7 pp 5648ndash5652 1993

[32] C Lee W Yang and R G Parr ldquoDevelopment of the Colle-Salvetti correlation-energy formula into a functional of theelectron densityrdquo Physical Review B vol 37 no 2 pp 785ndash7891988

[33] H Yoshida K Takeda J Okamura A Ehara and H MatsuuraldquoA new approach to vibrational analysis of large molecules bydensity functional theory wavenumber-linear scalingmethodrdquoJournal of Physical Chemistry A vol 106 no 14 pp 3580ndash35862002

14 Organic Chemistry International

[34] H Yoshida A Ehara and H Matsuura ldquoDensity functionalvibrational analysis using wavenumber-linear scale factorsrdquoChemical Physics Letters vol 325 no 4 pp 477ndash483 2000

[35] M J Frisch G W Trucks H B Schlegel et al Gaussian 03Revision B 01 Gaussian Pittsburgh Pa USA 2003

[36] J M L Martin and C Van Alsenoy GAR2PED A Program toObtain a Potential Energy Distribution from a Gaussian ArchiveRecord University of Antwerp 2009

[37] P Pulay G Fogarasi F Pang and J E Boggs ldquoSystematicab initio gradient calculation of molecular geometries forceconstants and dipole moment derivativesrdquo Journal of theAmerican Chemical Society vol 101 no 10 pp 2550ndash2560 1979

[38] S Mishra D Chaturvedi N Kumar P Tandon and H WSiesler ldquoAn ab initio and DFT study of structure and vibrationalspectra of 120574 form of Oleic acid comparison to experimentaldatardquo Chemistry and Physics of Lipids vol 163 no 2 pp 207ndash217 2010

[39] W O George D V Hassid and W F Maddams ldquoConfor-mations of some 120572120573-unsaturated carbonyl compoundsmdashpartIII infrared solution spectra of methyl [2H3]methyl ethyland [2H5]ethyl acrylates and trans-crotonatesrdquo Journal of theChemical Society Perkin Transactions 2 no 4 pp 400ndash4041972

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

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Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Medicinal ChemistryInternational Journal of

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Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

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Theoretical ChemistryJournal of

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Journal of

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Analytical ChemistryInternational Journal of

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Journal of

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Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

Page 10: Research Article Molecular Structure and Vibrational Spectra ...e molecular geometry, vibrational frequencies, and infrared intensities have been calculated by using density functional

10 Organic Chemistry International

Table 3 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

46 mdash 1242923 122855525 17298 y (C21H2) (89)47 mdash 1258238 124337912 11546 120588 (C9C12C21) (35) 120596 (C21H2) (35) 120596 (C9H2) (27)48 mdash 12801017 126452842 779146 120596 (C21H2) (47) 120588 (C9C12C21) (37) 120588 (C9H2) (27)49 1272 1283202 126752616 3516365 120596 (C21H2) (60) y (C14H2) (27) y (C9H2) (10)50 mdash 12991286 128292094 44292 y (C9H2) (72) y (C21H2) (26)51 1295 13117811 129514505 72842 y (C14H2) (99)52 mdash 131875 130187577 68204 y (C14H2) (100)53 mdash 13264691 13093292 01479 y (C21H2) (97)54 mdash 13362199 131874163 04090 y (C24H2) (94) y (C21H2) (5)55 1340 1359997 134168063 10793 120596 (C21H2) (86) 120588 (C21C12C14) (7) 120596 (C9H2) (5)56 mdash 13800145 136097825 04801 120588 (C9C12C21) (43) 120575 (C9H12) (28) 120596 (C21H2) (25)

57 1357 13931134 137359902 28872 120596 (C9H2) (50) 120596 (C14H2) (23) 120575 (C21C12H13) (12) 120596(C21H2) (86)

58 mdash 14043849 138445461 09476 120596 (C21H2) (86) 120596 (C9H2) (12)59 mdash 14119509 139173911 08054 120596 (C9H2) (85) 120596 (C21H2) (14)60 1381 14145333 1394225 50233 120596 (C21H2) (54) 120596 (C9H2) (45)61 mdash 14173104 139689807 08100 120596 (C21H2) (89) 120596 (C9H2) (8)62 1408 14414398 142011302 305726 120596 (C9H2) (93) 120596 (C21H2) (5)

63 mdash 14831028 146015241 20326 120575 (C9H2) (38) 120575 (C21C12H13) (18) 120575 (C24C21C12) (15) 120575(C14H2) (13) 120575 (C24H2) (7) 120575 (C21H2) (6)

64 mdash 14876468 146451591 04300 120575 (C21C12H13) (33) 120575 (C27H2) (28) 120575 (C24H2) (20) 120575(C21H2) (10)

65 mdash 14916884 14683964 12432 120575 (C21H2) (54) 120575 (C9H2) (21) 120575 (C27H2) (11)

66 mdash 15000764 147644833 24692 120575 (C24H2) (32) 120575 (C21C12H13) (24) 120575 (C27H2) (8) 120575(C30H3) (8) 120575 (C21H2) (6)

67 mdash 1500718 147706413 70795 120575 (C30H3) (75) 120575 (C9H2) (11) 120575 (C27H2) (6)68 mdash 15025266 147879993 89950 120575 (C9H2) (74) 120575 (C17H3) (21)

69 1464 15081671 148421269 98400 120575 (C27H2) (26) 120575 (C30H3) (22) 120575 (C21H2) (14) 120575(C17H3) (14) 120575 (C24H2) (11)

70 mdash 15116225 148752807 105533 120575 (C21H2) (73) 120575 (C21C12H13) (6) 120575 (C24H2) (5) 120575(C17H3) (5)

71 mdash 1514069 14898752 56625 120575 (C24H2) (30) 120575 (C21H2) (29) 120575 (C21C24C27) (20) 120575(C27H2) (9)

72 1619 16787098 164738009 287096 ] (C1C4) (52) ] (C4C6) (22) 120575 (C9C12H13) (11) 120575(C21H2) (8)

73 1727 17668533 173134006 3155882 120575 (C9C12C21) (63) ] (C4C6) (16) 120575 (C21H2) (6) ](C6O7) (6)

74 mdash 2995932 287569419 20873 ] (C24H2) (35) ] (C14H2) (34) ] (C21H2) (25)

75 mdash 2998467 287800355 06759 ] (C24H2) (40) ] (C12H13) (29) ] (C21H2) (12) ](C14H2) (10)

76 mdash 3001649 288090203 135187 ] (C21H2) (92)77 mdash 30053152 288424116 132101 ] (C24H2) (87) ] (C24H2) (8)78 2861 3013385 289158948 585964 ] (C21H2) (45) ] (C30C32) (36) ] (C12H13) (12)79 2875 30178939 289569433 472871 ] (C30C32) (96)80 mdash 30236248 290091073 211397 ] (C14H12) (46) ] (C17H19) (32) ] (C17H18) (17)

81 mdash 30260401 290310887 159088 ] (C12H13) (30) ] (C17H19) (27) ] (C17H18) (13) ](C30C32) (12)

82 mdash 303455 291085214 329164 ] (C21H2) (66) ] (C14H2) (28)83 mdash 30404085 291618149 40314 ] (C21H2) (55) ] (C30H32) (27) ] (C12H13) (7)84 mdash 30437899 291925696 263738 ] (C21H2) (98)85 mdash 30609167 293482854 503404 ] (C21H2) (85) ] (C30C32) (12)86 2931 30786333 295092629 824131 ] (C30C32) (95)

Organic Chemistry International 11

Table 3 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

87 mdash 30833975 295525341 441245 ] (C30C32) (93)88 mdash 30842781 295605315 369537 ] (C17H19) (67) ] (C17H18) (18) ] (C21H2) (9)

89 mdash 30889498 296029541 151201 ] (C21H2) (52) ] (C9H2) (14) ] (C12H13) (14) ] (C14H2)(8) ] (C17H19) (7)

90 2961 30930704 296403663 595099 ] (C17H19) (36) ] (C14H2) (28) ] (C17H20) (10) ](C21H2) (10) ] (C17H18) (8) ] (C9H2) (6)

91 3038 31462567 301227655 52018 ] (C1C4) (50) ] (C1H2) (31) ] (C1H3) (10)92 3069 31857999 304808243 34136 ] (C4H5) (57) ] (C4C6) (23) ] (C1C4) (14)93 3104 3237707 309500628 44771 ] (C1H2) (70) ] (C1H3) (11) ] (C4H5) (7)aAssignments and potential energy distribution (PED) (contributing ge 5) for vibrational normal mode Types of vibration ] stretching 120575 deformation oout-of-plane bending 120596 wagging y twisting 120588 rocking 120591 torsion w weak m medium sh shoulderbNormal mode number

Abso

rban

ce

Wavenumbers (cmminus1)

121

08060402

01200 1300 1400 1500 1600 1700 1800

17721295

13401357

1381

14081464

1619 1637 1686

1727

(a)

IR in

tens

ity (k

mm

ol) 50

40

30

20

10

0

Wavenumbers (cmminus1)1200 1250 1300 1350 1400 1450 1500 1550 1600 1650 1700 1750 1800

1244 12841301

1311

1307

134113731390

1394

1417

14631476

14841491

1656

1735

(b)

IR in

tens

ity (k

mm

ol) 50

40

30

20

10

0

Wavenumbers (cmminus1)

1227

1264

12421284

1266

12941302

13411373 1393

1419

14601476

14871489

16461731

1200 1250 1300 1350 1400 1450 1500 1550 1600 1650 1700 1750 1800

(c)

Figure 3 Comparison of the experimental IR (a) C=O and C=C stretching and CH bending region (1800ndash1200 cmminus1) with the appropriatetheoretical B3LYP6-311+Glowastlowast spectra ((b) and (c)) for s-cis and s-trans 2-ethylhexyl acrylate respectively

are well correlated to the calculated peaks in DFT for bothconformers see Tables 2 and 3

The shoulders in the infrared spectrum at 1025 1015 cmminus1of weak to medium intensities may be correlated to the bands1037 1015 cmminus1 for s-cis and 1015 988 cmminus1 for the s-trans

conformer These bands are ascribed to the CH out-of-planebending modes of the vinyl group

The remaining bands of weak intensity in the experimen-tal IR spectrum are 909 896 and 852 cmminus1 These bandsare close to the ones at 911 996 and 847 cmminus1 for the s-cis

12 Organic Chemistry International

121

08060402

0700 800 900 1000 1100 1200

727 770

811

952 869909 933

962 9841015 1025

1057

11161060

1191

Abso

rban

ce

Wavenumbers (cmminus1)

(a)

20

10

0

728776 783

825

848895

900911 940 975

1000

10131037

1008 1152 11581180

1016

1139

1156

1191

700 800 900 1000 1100 1200Wavenumbers (cmminus1)

IR in

tens

ity (k

mm

ol)

(b)

725

775783

827

846 896

900

940 965

993

1009

10131021

1066

10331051

1054

1079 11381156

1171

700 800 900 1000 1100 1200Wavenumbers (cmminus1)

20

10

0IR in

tens

ity (k

mm

ol)

(c)

Figure 4 Comparison of the experimental IR (a) CO stretching and CH bending region (1200ndash700 cmminus1) with the appropriate theoreticalB3LYP6-311+Glowastlowast spectra ((b) and (c)) for s-cis and s-trans 2-ethylhexyl acrylate respectively

conformation of the titlemolecule All the vibrational normalmodes in this region are not pure and the majority of themwere ascribed according to PED calculations to CH bending(for more details see Tables 2 and 3)

54 Region below 700 cmminus1 This spectral region includesthe bands associated with C=CndashC CndashOndashC O=CndashO OndashCndashC CndashCndashC and CndashCndashC bending and torsion modes aboutthe single bonds OndashC and CndashC The frequencies and PEDcalculations are presented in Tables 2 and 3 Comparing the23 first normal modes for the two conformers we notice thatthey have the same type of vibrational modes However thenormal modes 16 17 and 18 represent CCC bending in the s-trans andCHandCCC rockingmodes in the s-cis conformer

Due to the lack of experimental data on this region wecompare our calculated frequencies to some experimental IRbands of related molecules presented in the literature Thebands at 356 254 116 and 100 cmminus1 are close to the bandsat 349(A1015840) 244(A10158401015840) 114(A10158401015840) and 114 cmminus1 (A10158401015840) reported byDulce et al [28] From the same work the bands at 530 244114 and 114 cmminus1 belonging to A10158401015840 symmetry for the s-trans

methyl acrylate in liquid state are close to our calculatedbands in DFT at 542 244 116 and 106 cmminus1

6 Conclusions

Themid-IR spectrum of 2-ethylhexyl acrylate was measuredand interpreted with support of the DFTB3LYP6-311+Glowastlowastcalculated vibrational spectra followed by potential energydistribution analysis Assuming the s-cis and s-trans confor-mations we found two stable conformations close in theirenergies The fully optimized geometries of s-cis and s-transconformations by DFTB3LYP6-311+Glowastlowast were comparedwith the experimental and theoretical data presented in theliterature on the methyl acrylate molecule The compari-son shows a good agreement The experimental vibrationalspectrum is in good agreement with the theoretical spectracalculated for the two conformations Two neighbor bandsin the IR spectrum at 1619 and 1637 cmminus1 may be used ascharacteristic bands to locate and distinguish the existence ofone or both conformations

Organic Chemistry International 13

References

[1] M Salkind E H Riddle and R W Keefer ldquoAcrylates andmethacrylates ester manufacture and marketsrdquo Industrial ampEngineering Chemistry Research vol 51 no 11 pp 1328ndash13341959

[2] K S Anseth S M Newman and C N Bowman ldquoPolymericdental composites properties and reaction behavior of multi-methacrylate dental restorationsrdquo Advances in Polymer Sciencevol 122 pp 176ndash217 1995

[3] J G Kloosterboer ldquoNetwork formation by chain crosslink-ing photopolymerization and its application in electronicsrdquoAdvances in Polymer Science vol 84 pp 1ndash61 1988

[4] K Matyjaszewski Y Gnanou and L Leibler MacromolecularEngineering vol 1 Wiley-VCH Weinheim Germany 2007

[5] M Orgill B L Baker and N L Owen ldquoFTIR studies ofconformational isomerism in acrylates and acrylic acidsrdquo Spec-trochimica Acta A vol 55 no 5 pp 1021ndash1024 1999

[6] M Salkind ldquoReaches into the marketrdquo Industrial amp EngineeringChemistry Research vol 56 pp 62ndash110 1964

[7] E Takacs K Dajka and L Wojnarovits ldquoStudy of high-energyradiation initiated polymerization of butyl acrylaterdquo RadiationPhysics and Chemistry vol 63 no 1 pp 41ndash44 2002

[8] H Yu J Peng M Zhai J Li G Wei and J Qiao ldquoRadiation-induced copolymerization of styrenen-butyl acrylate in thepresence of ultra-fine powdered styrene-butadiene rubberrdquoRadiation Physics and Chemistry vol 76 no 11-12 pp 1736ndash1740 2007

[9] P F Canamero J Luis de la Fuente and M Fermandez-GarcıaldquoCuring kinetic study using a well-controlled multifunctionalcopolymer based on glycidyl methacrylaterdquo European PolymerJournal vol 45 no 9 pp 2665ndash2673 2009

[10] DMathew C P ReghunadhanNair and K N Ninan ldquoPendantcyanate functional vinyl polymers and imidophenolic-triazinesthereof synthesis and thermal propertiesrdquo European PolymerJournal vol 36 no 6 pp 1195ndash1208 2000

[11] S Mitra S Chattopadhyay S Sabharwal and A K BhowmickldquoElectron beam crosslinked gels-Preparation characterizationand their effect on the mechanical dynamic mechanical andrheological properties of rubbersrdquoRadiation Physics and Chem-istry vol 79 no 2 pp 289ndash296 2010

[12] P Canamero-Martınez M Fermandez-Garcıa and J Luis de laFuente ldquoRheological cure characterization of a polyfunctionalepoxy acrylic resinrdquo Reactive and Functional Polymers vol 70no 10 pp 761ndash766 2010

[13] F Chu T McKenna and S Lu ldquoCuring kinetics of an acrylicresinepoxy resin system using dynamic scanning calorimetryrdquoEuropean Polymer Journal vol 33 no 6 pp 837ndash840 1997

[14] M C Douskey M S Gebhard A V McCormick et alldquoSpectroscopic studies of a novel cyclic oligomer with pendantalkoxysilane groupsrdquo Progress in Organic Coatings vol 45 no2-3 pp 145ndash157 2002

[15] R J Day P A Lovell and A A Wazzan ldquoToughened car-bonepoxy composites made by using coreshell particlesrdquoComposites Science andTechnology vol 61 no 1 pp 41ndash56 2001

[16] K Bolton D G Lister and J Sheridan ldquoRotational isomerismbarrier to internal rotation and electric dipole moment ofacrylic acid bymicrowave spectroscopyrdquo Journal of the ChemicalSociety Faraday Transactions 2 vol 70 pp 113ndash123 1974

[17] S W Charles F C Cullen N L Owen and G A WilliamsldquoInfrared spectrum and rotational isomerism of acrylic acidrdquoJournal of Molecular Structure vol 157 no 1ndash3 pp 17ndash25 1987

[18] K Bolton N L Owen and J Sheridan ldquoMicrowave spectra ofrotational isomers of acrylic acidrdquoNature vol 218 no 5138 pp266ndash267 1968

[19] G Williams N L Owen and J Sheridan ldquoSpectroscopicstudies of some substitutedmethyl formatesmdashpart 1microwavespectra and internal rotation barriers of methyl-fluoroformate-propiolate -cyanoformate -acrylate and -acetaterdquo Transac-tions of the Faraday Society vol 67 pp 922ndash949 1971

[20] T Tsuji H Ito H Takeuchi and S Konaka ldquoMolecularstructure and conformation ofmethylmethacrylate determinedby gas electron diffractionrdquo Journal of Molecular Structure vol475 no 1 pp 55ndash63 1999

[21] T Egawa S Maekawa H Fujiwara Takeuchi H Takeuchi andS Konaka ldquoMolecular structure and conformation of methylacrylate a gas electron diffraction study augmented by ab initiocalculation and rotational constantsrdquo Molecular Structure andSpectroscopy vol 352 pp 193ndash201 1995

[22] A Virdi V P Gupta and A Sharma ldquoAb initio studies onconformation vibrational and electronic spectra of methylmethacrylaterdquo Journal ofMolecular Structure vol 634 no 5 pp53ndash65 2003

[23] B L Baker M Orgill N L Owen et al ldquoThe molecularconformation of methyl methacrylatemdashan infrared and abinitio studyrdquo Journal of Molecular Structure vol 356 no 2 pp95ndash104 1995

[24] A N Mitra and I Santhanan ldquoRelativistic qqq spectra fromBethe-Salpeter premisesrdquo Physics Letters B vol 104 no 1 pp62ndash66 1981

[25] K Fan and J E Boggs ldquoRotational isomerism of acrylic acidrdquoJournal of Molecular Structure vol 157 no 1ndash3 pp 31ndash41 1987

[26] P Carmona and J Moreno ldquoThe infrared spectra and structureof methyl acrylaterdquo Journal of Molecular Structure vol 82 no3-4 pp 177ndash185 1982

[27] R J Loncharich T R Schwartz and K N Houk ldquoTheoreticalstudies of conformations of acrolein acrylic acid methyl acry-late and their Lewis acid complexesrdquo Journal of the AmericanChemical Society vol 109 no 1 pp 14ndash23 1987

[28] M Dulce G Faria J J C Teixeira-Dias and R FaustoldquoVibrational spectra and structure of methyl trans-crotonaterdquoVibrational Spectroscopy vol 2 no 2-3 pp 43ndash60 1991

[29] J J C Teixeira-Dias and R Fausto ldquoMolecular structure ofmethyl acrylate the high energy s-trans-(CO) conformerrdquoJournal of Molecular Structure vol 282 no 1-2 pp 123ndash1291993

[30] A J Bowles W O George and D B Cunliffe-Jones ldquoConfor-mations of some120572120573-unsaturated carbonyl compoundsmdashpart IIinfrared and Raman spectra of methyl and ethyl acrylates andtranscrotonatesrdquo Journal of the Chemical Society B pp 1070ndash1075 1970

[31] A D Becke ldquoDensity-functional thermochemistry IIIThe roleof exact exchangerdquoThe Journal of Chemical Physics vol 98 no7 pp 5648ndash5652 1993

[32] C Lee W Yang and R G Parr ldquoDevelopment of the Colle-Salvetti correlation-energy formula into a functional of theelectron densityrdquo Physical Review B vol 37 no 2 pp 785ndash7891988

[33] H Yoshida K Takeda J Okamura A Ehara and H MatsuuraldquoA new approach to vibrational analysis of large molecules bydensity functional theory wavenumber-linear scalingmethodrdquoJournal of Physical Chemistry A vol 106 no 14 pp 3580ndash35862002

14 Organic Chemistry International

[34] H Yoshida A Ehara and H Matsuura ldquoDensity functionalvibrational analysis using wavenumber-linear scale factorsrdquoChemical Physics Letters vol 325 no 4 pp 477ndash483 2000

[35] M J Frisch G W Trucks H B Schlegel et al Gaussian 03Revision B 01 Gaussian Pittsburgh Pa USA 2003

[36] J M L Martin and C Van Alsenoy GAR2PED A Program toObtain a Potential Energy Distribution from a Gaussian ArchiveRecord University of Antwerp 2009

[37] P Pulay G Fogarasi F Pang and J E Boggs ldquoSystematicab initio gradient calculation of molecular geometries forceconstants and dipole moment derivativesrdquo Journal of theAmerican Chemical Society vol 101 no 10 pp 2550ndash2560 1979

[38] S Mishra D Chaturvedi N Kumar P Tandon and H WSiesler ldquoAn ab initio and DFT study of structure and vibrationalspectra of 120574 form of Oleic acid comparison to experimentaldatardquo Chemistry and Physics of Lipids vol 163 no 2 pp 207ndash217 2010

[39] W O George D V Hassid and W F Maddams ldquoConfor-mations of some 120572120573-unsaturated carbonyl compoundsmdashpartIII infrared solution spectra of methyl [2H3]methyl ethyland [2H5]ethyl acrylates and trans-crotonatesrdquo Journal of theChemical Society Perkin Transactions 2 no 4 pp 400ndash4041972

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

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Analytical Methods in Chemistry

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Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

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The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

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Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Theoretical ChemistryJournal of

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Journal of

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Quantum Chemistry

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CatalystsJournal of

Page 11: Research Article Molecular Structure and Vibrational Spectra ...e molecular geometry, vibrational frequencies, and infrared intensities have been calculated by using density functional

Organic Chemistry International 11

Table 3 Continued

Numberb Observed(cmminus1)

DFT6-311+GlowastlowastUnscaled (cmminus1) Scaled (cmminus1) Intensity

(kmsdotmolminus1) Assignment (PED)a

87 mdash 30833975 295525341 441245 ] (C30C32) (93)88 mdash 30842781 295605315 369537 ] (C17H19) (67) ] (C17H18) (18) ] (C21H2) (9)

89 mdash 30889498 296029541 151201 ] (C21H2) (52) ] (C9H2) (14) ] (C12H13) (14) ] (C14H2)(8) ] (C17H19) (7)

90 2961 30930704 296403663 595099 ] (C17H19) (36) ] (C14H2) (28) ] (C17H20) (10) ](C21H2) (10) ] (C17H18) (8) ] (C9H2) (6)

91 3038 31462567 301227655 52018 ] (C1C4) (50) ] (C1H2) (31) ] (C1H3) (10)92 3069 31857999 304808243 34136 ] (C4H5) (57) ] (C4C6) (23) ] (C1C4) (14)93 3104 3237707 309500628 44771 ] (C1H2) (70) ] (C1H3) (11) ] (C4H5) (7)aAssignments and potential energy distribution (PED) (contributing ge 5) for vibrational normal mode Types of vibration ] stretching 120575 deformation oout-of-plane bending 120596 wagging y twisting 120588 rocking 120591 torsion w weak m medium sh shoulderbNormal mode number

Abso

rban

ce

Wavenumbers (cmminus1)

121

08060402

01200 1300 1400 1500 1600 1700 1800

17721295

13401357

1381

14081464

1619 1637 1686

1727

(a)

IR in

tens

ity (k

mm

ol) 50

40

30

20

10

0

Wavenumbers (cmminus1)1200 1250 1300 1350 1400 1450 1500 1550 1600 1650 1700 1750 1800

1244 12841301

1311

1307

134113731390

1394

1417

14631476

14841491

1656

1735

(b)

IR in

tens

ity (k

mm

ol) 50

40

30

20

10

0

Wavenumbers (cmminus1)

1227

1264

12421284

1266

12941302

13411373 1393

1419

14601476

14871489

16461731

1200 1250 1300 1350 1400 1450 1500 1550 1600 1650 1700 1750 1800

(c)

Figure 3 Comparison of the experimental IR (a) C=O and C=C stretching and CH bending region (1800ndash1200 cmminus1) with the appropriatetheoretical B3LYP6-311+Glowastlowast spectra ((b) and (c)) for s-cis and s-trans 2-ethylhexyl acrylate respectively

are well correlated to the calculated peaks in DFT for bothconformers see Tables 2 and 3

The shoulders in the infrared spectrum at 1025 1015 cmminus1of weak to medium intensities may be correlated to the bands1037 1015 cmminus1 for s-cis and 1015 988 cmminus1 for the s-trans

conformer These bands are ascribed to the CH out-of-planebending modes of the vinyl group

The remaining bands of weak intensity in the experimen-tal IR spectrum are 909 896 and 852 cmminus1 These bandsare close to the ones at 911 996 and 847 cmminus1 for the s-cis

12 Organic Chemistry International

121

08060402

0700 800 900 1000 1100 1200

727 770

811

952 869909 933

962 9841015 1025

1057

11161060

1191

Abso

rban

ce

Wavenumbers (cmminus1)

(a)

20

10

0

728776 783

825

848895

900911 940 975

1000

10131037

1008 1152 11581180

1016

1139

1156

1191

700 800 900 1000 1100 1200Wavenumbers (cmminus1)

IR in

tens

ity (k

mm

ol)

(b)

725

775783

827

846 896

900

940 965

993

1009

10131021

1066

10331051

1054

1079 11381156

1171

700 800 900 1000 1100 1200Wavenumbers (cmminus1)

20

10

0IR in

tens

ity (k

mm

ol)

(c)

Figure 4 Comparison of the experimental IR (a) CO stretching and CH bending region (1200ndash700 cmminus1) with the appropriate theoreticalB3LYP6-311+Glowastlowast spectra ((b) and (c)) for s-cis and s-trans 2-ethylhexyl acrylate respectively

conformation of the titlemolecule All the vibrational normalmodes in this region are not pure and the majority of themwere ascribed according to PED calculations to CH bending(for more details see Tables 2 and 3)

54 Region below 700 cmminus1 This spectral region includesthe bands associated with C=CndashC CndashOndashC O=CndashO OndashCndashC CndashCndashC and CndashCndashC bending and torsion modes aboutthe single bonds OndashC and CndashC The frequencies and PEDcalculations are presented in Tables 2 and 3 Comparing the23 first normal modes for the two conformers we notice thatthey have the same type of vibrational modes However thenormal modes 16 17 and 18 represent CCC bending in the s-trans andCHandCCC rockingmodes in the s-cis conformer

Due to the lack of experimental data on this region wecompare our calculated frequencies to some experimental IRbands of related molecules presented in the literature Thebands at 356 254 116 and 100 cmminus1 are close to the bandsat 349(A1015840) 244(A10158401015840) 114(A10158401015840) and 114 cmminus1 (A10158401015840) reported byDulce et al [28] From the same work the bands at 530 244114 and 114 cmminus1 belonging to A10158401015840 symmetry for the s-trans

methyl acrylate in liquid state are close to our calculatedbands in DFT at 542 244 116 and 106 cmminus1

6 Conclusions

Themid-IR spectrum of 2-ethylhexyl acrylate was measuredand interpreted with support of the DFTB3LYP6-311+Glowastlowastcalculated vibrational spectra followed by potential energydistribution analysis Assuming the s-cis and s-trans confor-mations we found two stable conformations close in theirenergies The fully optimized geometries of s-cis and s-transconformations by DFTB3LYP6-311+Glowastlowast were comparedwith the experimental and theoretical data presented in theliterature on the methyl acrylate molecule The compari-son shows a good agreement The experimental vibrationalspectrum is in good agreement with the theoretical spectracalculated for the two conformations Two neighbor bandsin the IR spectrum at 1619 and 1637 cmminus1 may be used ascharacteristic bands to locate and distinguish the existence ofone or both conformations

Organic Chemistry International 13

References

[1] M Salkind E H Riddle and R W Keefer ldquoAcrylates andmethacrylates ester manufacture and marketsrdquo Industrial ampEngineering Chemistry Research vol 51 no 11 pp 1328ndash13341959

[2] K S Anseth S M Newman and C N Bowman ldquoPolymericdental composites properties and reaction behavior of multi-methacrylate dental restorationsrdquo Advances in Polymer Sciencevol 122 pp 176ndash217 1995

[3] J G Kloosterboer ldquoNetwork formation by chain crosslink-ing photopolymerization and its application in electronicsrdquoAdvances in Polymer Science vol 84 pp 1ndash61 1988

[4] K Matyjaszewski Y Gnanou and L Leibler MacromolecularEngineering vol 1 Wiley-VCH Weinheim Germany 2007

[5] M Orgill B L Baker and N L Owen ldquoFTIR studies ofconformational isomerism in acrylates and acrylic acidsrdquo Spec-trochimica Acta A vol 55 no 5 pp 1021ndash1024 1999

[6] M Salkind ldquoReaches into the marketrdquo Industrial amp EngineeringChemistry Research vol 56 pp 62ndash110 1964

[7] E Takacs K Dajka and L Wojnarovits ldquoStudy of high-energyradiation initiated polymerization of butyl acrylaterdquo RadiationPhysics and Chemistry vol 63 no 1 pp 41ndash44 2002

[8] H Yu J Peng M Zhai J Li G Wei and J Qiao ldquoRadiation-induced copolymerization of styrenen-butyl acrylate in thepresence of ultra-fine powdered styrene-butadiene rubberrdquoRadiation Physics and Chemistry vol 76 no 11-12 pp 1736ndash1740 2007

[9] P F Canamero J Luis de la Fuente and M Fermandez-GarcıaldquoCuring kinetic study using a well-controlled multifunctionalcopolymer based on glycidyl methacrylaterdquo European PolymerJournal vol 45 no 9 pp 2665ndash2673 2009

[10] DMathew C P ReghunadhanNair and K N Ninan ldquoPendantcyanate functional vinyl polymers and imidophenolic-triazinesthereof synthesis and thermal propertiesrdquo European PolymerJournal vol 36 no 6 pp 1195ndash1208 2000

[11] S Mitra S Chattopadhyay S Sabharwal and A K BhowmickldquoElectron beam crosslinked gels-Preparation characterizationand their effect on the mechanical dynamic mechanical andrheological properties of rubbersrdquoRadiation Physics and Chem-istry vol 79 no 2 pp 289ndash296 2010

[12] P Canamero-Martınez M Fermandez-Garcıa and J Luis de laFuente ldquoRheological cure characterization of a polyfunctionalepoxy acrylic resinrdquo Reactive and Functional Polymers vol 70no 10 pp 761ndash766 2010

[13] F Chu T McKenna and S Lu ldquoCuring kinetics of an acrylicresinepoxy resin system using dynamic scanning calorimetryrdquoEuropean Polymer Journal vol 33 no 6 pp 837ndash840 1997

[14] M C Douskey M S Gebhard A V McCormick et alldquoSpectroscopic studies of a novel cyclic oligomer with pendantalkoxysilane groupsrdquo Progress in Organic Coatings vol 45 no2-3 pp 145ndash157 2002

[15] R J Day P A Lovell and A A Wazzan ldquoToughened car-bonepoxy composites made by using coreshell particlesrdquoComposites Science andTechnology vol 61 no 1 pp 41ndash56 2001

[16] K Bolton D G Lister and J Sheridan ldquoRotational isomerismbarrier to internal rotation and electric dipole moment ofacrylic acid bymicrowave spectroscopyrdquo Journal of the ChemicalSociety Faraday Transactions 2 vol 70 pp 113ndash123 1974

[17] S W Charles F C Cullen N L Owen and G A WilliamsldquoInfrared spectrum and rotational isomerism of acrylic acidrdquoJournal of Molecular Structure vol 157 no 1ndash3 pp 17ndash25 1987

[18] K Bolton N L Owen and J Sheridan ldquoMicrowave spectra ofrotational isomers of acrylic acidrdquoNature vol 218 no 5138 pp266ndash267 1968

[19] G Williams N L Owen and J Sheridan ldquoSpectroscopicstudies of some substitutedmethyl formatesmdashpart 1microwavespectra and internal rotation barriers of methyl-fluoroformate-propiolate -cyanoformate -acrylate and -acetaterdquo Transac-tions of the Faraday Society vol 67 pp 922ndash949 1971

[20] T Tsuji H Ito H Takeuchi and S Konaka ldquoMolecularstructure and conformation ofmethylmethacrylate determinedby gas electron diffractionrdquo Journal of Molecular Structure vol475 no 1 pp 55ndash63 1999

[21] T Egawa S Maekawa H Fujiwara Takeuchi H Takeuchi andS Konaka ldquoMolecular structure and conformation of methylacrylate a gas electron diffraction study augmented by ab initiocalculation and rotational constantsrdquo Molecular Structure andSpectroscopy vol 352 pp 193ndash201 1995

[22] A Virdi V P Gupta and A Sharma ldquoAb initio studies onconformation vibrational and electronic spectra of methylmethacrylaterdquo Journal ofMolecular Structure vol 634 no 5 pp53ndash65 2003

[23] B L Baker M Orgill N L Owen et al ldquoThe molecularconformation of methyl methacrylatemdashan infrared and abinitio studyrdquo Journal of Molecular Structure vol 356 no 2 pp95ndash104 1995

[24] A N Mitra and I Santhanan ldquoRelativistic qqq spectra fromBethe-Salpeter premisesrdquo Physics Letters B vol 104 no 1 pp62ndash66 1981

[25] K Fan and J E Boggs ldquoRotational isomerism of acrylic acidrdquoJournal of Molecular Structure vol 157 no 1ndash3 pp 31ndash41 1987

[26] P Carmona and J Moreno ldquoThe infrared spectra and structureof methyl acrylaterdquo Journal of Molecular Structure vol 82 no3-4 pp 177ndash185 1982

[27] R J Loncharich T R Schwartz and K N Houk ldquoTheoreticalstudies of conformations of acrolein acrylic acid methyl acry-late and their Lewis acid complexesrdquo Journal of the AmericanChemical Society vol 109 no 1 pp 14ndash23 1987

[28] M Dulce G Faria J J C Teixeira-Dias and R FaustoldquoVibrational spectra and structure of methyl trans-crotonaterdquoVibrational Spectroscopy vol 2 no 2-3 pp 43ndash60 1991

[29] J J C Teixeira-Dias and R Fausto ldquoMolecular structure ofmethyl acrylate the high energy s-trans-(CO) conformerrdquoJournal of Molecular Structure vol 282 no 1-2 pp 123ndash1291993

[30] A J Bowles W O George and D B Cunliffe-Jones ldquoConfor-mations of some120572120573-unsaturated carbonyl compoundsmdashpart IIinfrared and Raman spectra of methyl and ethyl acrylates andtranscrotonatesrdquo Journal of the Chemical Society B pp 1070ndash1075 1970

[31] A D Becke ldquoDensity-functional thermochemistry IIIThe roleof exact exchangerdquoThe Journal of Chemical Physics vol 98 no7 pp 5648ndash5652 1993

[32] C Lee W Yang and R G Parr ldquoDevelopment of the Colle-Salvetti correlation-energy formula into a functional of theelectron densityrdquo Physical Review B vol 37 no 2 pp 785ndash7891988

[33] H Yoshida K Takeda J Okamura A Ehara and H MatsuuraldquoA new approach to vibrational analysis of large molecules bydensity functional theory wavenumber-linear scalingmethodrdquoJournal of Physical Chemistry A vol 106 no 14 pp 3580ndash35862002

14 Organic Chemistry International

[34] H Yoshida A Ehara and H Matsuura ldquoDensity functionalvibrational analysis using wavenumber-linear scale factorsrdquoChemical Physics Letters vol 325 no 4 pp 477ndash483 2000

[35] M J Frisch G W Trucks H B Schlegel et al Gaussian 03Revision B 01 Gaussian Pittsburgh Pa USA 2003

[36] J M L Martin and C Van Alsenoy GAR2PED A Program toObtain a Potential Energy Distribution from a Gaussian ArchiveRecord University of Antwerp 2009

[37] P Pulay G Fogarasi F Pang and J E Boggs ldquoSystematicab initio gradient calculation of molecular geometries forceconstants and dipole moment derivativesrdquo Journal of theAmerican Chemical Society vol 101 no 10 pp 2550ndash2560 1979

[38] S Mishra D Chaturvedi N Kumar P Tandon and H WSiesler ldquoAn ab initio and DFT study of structure and vibrationalspectra of 120574 form of Oleic acid comparison to experimentaldatardquo Chemistry and Physics of Lipids vol 163 no 2 pp 207ndash217 2010

[39] W O George D V Hassid and W F Maddams ldquoConfor-mations of some 120572120573-unsaturated carbonyl compoundsmdashpartIII infrared solution spectra of methyl [2H3]methyl ethyland [2H5]ethyl acrylates and trans-crotonatesrdquo Journal of theChemical Society Perkin Transactions 2 no 4 pp 400ndash4041972

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

Page 12: Research Article Molecular Structure and Vibrational Spectra ...e molecular geometry, vibrational frequencies, and infrared intensities have been calculated by using density functional

12 Organic Chemistry International

121

08060402

0700 800 900 1000 1100 1200

727 770

811

952 869909 933

962 9841015 1025

1057

11161060

1191

Abso

rban

ce

Wavenumbers (cmminus1)

(a)

20

10

0

728776 783

825

848895

900911 940 975

1000

10131037

1008 1152 11581180

1016

1139

1156

1191

700 800 900 1000 1100 1200Wavenumbers (cmminus1)

IR in

tens

ity (k

mm

ol)

(b)

725

775783

827

846 896

900

940 965

993

1009

10131021

1066

10331051

1054

1079 11381156

1171

700 800 900 1000 1100 1200Wavenumbers (cmminus1)

20

10

0IR in

tens

ity (k

mm

ol)

(c)

Figure 4 Comparison of the experimental IR (a) CO stretching and CH bending region (1200ndash700 cmminus1) with the appropriate theoreticalB3LYP6-311+Glowastlowast spectra ((b) and (c)) for s-cis and s-trans 2-ethylhexyl acrylate respectively

conformation of the titlemolecule All the vibrational normalmodes in this region are not pure and the majority of themwere ascribed according to PED calculations to CH bending(for more details see Tables 2 and 3)

54 Region below 700 cmminus1 This spectral region includesthe bands associated with C=CndashC CndashOndashC O=CndashO OndashCndashC CndashCndashC and CndashCndashC bending and torsion modes aboutthe single bonds OndashC and CndashC The frequencies and PEDcalculations are presented in Tables 2 and 3 Comparing the23 first normal modes for the two conformers we notice thatthey have the same type of vibrational modes However thenormal modes 16 17 and 18 represent CCC bending in the s-trans andCHandCCC rockingmodes in the s-cis conformer

Due to the lack of experimental data on this region wecompare our calculated frequencies to some experimental IRbands of related molecules presented in the literature Thebands at 356 254 116 and 100 cmminus1 are close to the bandsat 349(A1015840) 244(A10158401015840) 114(A10158401015840) and 114 cmminus1 (A10158401015840) reported byDulce et al [28] From the same work the bands at 530 244114 and 114 cmminus1 belonging to A10158401015840 symmetry for the s-trans

methyl acrylate in liquid state are close to our calculatedbands in DFT at 542 244 116 and 106 cmminus1

6 Conclusions

Themid-IR spectrum of 2-ethylhexyl acrylate was measuredand interpreted with support of the DFTB3LYP6-311+Glowastlowastcalculated vibrational spectra followed by potential energydistribution analysis Assuming the s-cis and s-trans confor-mations we found two stable conformations close in theirenergies The fully optimized geometries of s-cis and s-transconformations by DFTB3LYP6-311+Glowastlowast were comparedwith the experimental and theoretical data presented in theliterature on the methyl acrylate molecule The compari-son shows a good agreement The experimental vibrationalspectrum is in good agreement with the theoretical spectracalculated for the two conformations Two neighbor bandsin the IR spectrum at 1619 and 1637 cmminus1 may be used ascharacteristic bands to locate and distinguish the existence ofone or both conformations

Organic Chemistry International 13

References

[1] M Salkind E H Riddle and R W Keefer ldquoAcrylates andmethacrylates ester manufacture and marketsrdquo Industrial ampEngineering Chemistry Research vol 51 no 11 pp 1328ndash13341959

[2] K S Anseth S M Newman and C N Bowman ldquoPolymericdental composites properties and reaction behavior of multi-methacrylate dental restorationsrdquo Advances in Polymer Sciencevol 122 pp 176ndash217 1995

[3] J G Kloosterboer ldquoNetwork formation by chain crosslink-ing photopolymerization and its application in electronicsrdquoAdvances in Polymer Science vol 84 pp 1ndash61 1988

[4] K Matyjaszewski Y Gnanou and L Leibler MacromolecularEngineering vol 1 Wiley-VCH Weinheim Germany 2007

[5] M Orgill B L Baker and N L Owen ldquoFTIR studies ofconformational isomerism in acrylates and acrylic acidsrdquo Spec-trochimica Acta A vol 55 no 5 pp 1021ndash1024 1999

[6] M Salkind ldquoReaches into the marketrdquo Industrial amp EngineeringChemistry Research vol 56 pp 62ndash110 1964

[7] E Takacs K Dajka and L Wojnarovits ldquoStudy of high-energyradiation initiated polymerization of butyl acrylaterdquo RadiationPhysics and Chemistry vol 63 no 1 pp 41ndash44 2002

[8] H Yu J Peng M Zhai J Li G Wei and J Qiao ldquoRadiation-induced copolymerization of styrenen-butyl acrylate in thepresence of ultra-fine powdered styrene-butadiene rubberrdquoRadiation Physics and Chemistry vol 76 no 11-12 pp 1736ndash1740 2007

[9] P F Canamero J Luis de la Fuente and M Fermandez-GarcıaldquoCuring kinetic study using a well-controlled multifunctionalcopolymer based on glycidyl methacrylaterdquo European PolymerJournal vol 45 no 9 pp 2665ndash2673 2009

[10] DMathew C P ReghunadhanNair and K N Ninan ldquoPendantcyanate functional vinyl polymers and imidophenolic-triazinesthereof synthesis and thermal propertiesrdquo European PolymerJournal vol 36 no 6 pp 1195ndash1208 2000

[11] S Mitra S Chattopadhyay S Sabharwal and A K BhowmickldquoElectron beam crosslinked gels-Preparation characterizationand their effect on the mechanical dynamic mechanical andrheological properties of rubbersrdquoRadiation Physics and Chem-istry vol 79 no 2 pp 289ndash296 2010

[12] P Canamero-Martınez M Fermandez-Garcıa and J Luis de laFuente ldquoRheological cure characterization of a polyfunctionalepoxy acrylic resinrdquo Reactive and Functional Polymers vol 70no 10 pp 761ndash766 2010

[13] F Chu T McKenna and S Lu ldquoCuring kinetics of an acrylicresinepoxy resin system using dynamic scanning calorimetryrdquoEuropean Polymer Journal vol 33 no 6 pp 837ndash840 1997

[14] M C Douskey M S Gebhard A V McCormick et alldquoSpectroscopic studies of a novel cyclic oligomer with pendantalkoxysilane groupsrdquo Progress in Organic Coatings vol 45 no2-3 pp 145ndash157 2002

[15] R J Day P A Lovell and A A Wazzan ldquoToughened car-bonepoxy composites made by using coreshell particlesrdquoComposites Science andTechnology vol 61 no 1 pp 41ndash56 2001

[16] K Bolton D G Lister and J Sheridan ldquoRotational isomerismbarrier to internal rotation and electric dipole moment ofacrylic acid bymicrowave spectroscopyrdquo Journal of the ChemicalSociety Faraday Transactions 2 vol 70 pp 113ndash123 1974

[17] S W Charles F C Cullen N L Owen and G A WilliamsldquoInfrared spectrum and rotational isomerism of acrylic acidrdquoJournal of Molecular Structure vol 157 no 1ndash3 pp 17ndash25 1987

[18] K Bolton N L Owen and J Sheridan ldquoMicrowave spectra ofrotational isomers of acrylic acidrdquoNature vol 218 no 5138 pp266ndash267 1968

[19] G Williams N L Owen and J Sheridan ldquoSpectroscopicstudies of some substitutedmethyl formatesmdashpart 1microwavespectra and internal rotation barriers of methyl-fluoroformate-propiolate -cyanoformate -acrylate and -acetaterdquo Transac-tions of the Faraday Society vol 67 pp 922ndash949 1971

[20] T Tsuji H Ito H Takeuchi and S Konaka ldquoMolecularstructure and conformation ofmethylmethacrylate determinedby gas electron diffractionrdquo Journal of Molecular Structure vol475 no 1 pp 55ndash63 1999

[21] T Egawa S Maekawa H Fujiwara Takeuchi H Takeuchi andS Konaka ldquoMolecular structure and conformation of methylacrylate a gas electron diffraction study augmented by ab initiocalculation and rotational constantsrdquo Molecular Structure andSpectroscopy vol 352 pp 193ndash201 1995

[22] A Virdi V P Gupta and A Sharma ldquoAb initio studies onconformation vibrational and electronic spectra of methylmethacrylaterdquo Journal ofMolecular Structure vol 634 no 5 pp53ndash65 2003

[23] B L Baker M Orgill N L Owen et al ldquoThe molecularconformation of methyl methacrylatemdashan infrared and abinitio studyrdquo Journal of Molecular Structure vol 356 no 2 pp95ndash104 1995

[24] A N Mitra and I Santhanan ldquoRelativistic qqq spectra fromBethe-Salpeter premisesrdquo Physics Letters B vol 104 no 1 pp62ndash66 1981

[25] K Fan and J E Boggs ldquoRotational isomerism of acrylic acidrdquoJournal of Molecular Structure vol 157 no 1ndash3 pp 31ndash41 1987

[26] P Carmona and J Moreno ldquoThe infrared spectra and structureof methyl acrylaterdquo Journal of Molecular Structure vol 82 no3-4 pp 177ndash185 1982

[27] R J Loncharich T R Schwartz and K N Houk ldquoTheoreticalstudies of conformations of acrolein acrylic acid methyl acry-late and their Lewis acid complexesrdquo Journal of the AmericanChemical Society vol 109 no 1 pp 14ndash23 1987

[28] M Dulce G Faria J J C Teixeira-Dias and R FaustoldquoVibrational spectra and structure of methyl trans-crotonaterdquoVibrational Spectroscopy vol 2 no 2-3 pp 43ndash60 1991

[29] J J C Teixeira-Dias and R Fausto ldquoMolecular structure ofmethyl acrylate the high energy s-trans-(CO) conformerrdquoJournal of Molecular Structure vol 282 no 1-2 pp 123ndash1291993

[30] A J Bowles W O George and D B Cunliffe-Jones ldquoConfor-mations of some120572120573-unsaturated carbonyl compoundsmdashpart IIinfrared and Raman spectra of methyl and ethyl acrylates andtranscrotonatesrdquo Journal of the Chemical Society B pp 1070ndash1075 1970

[31] A D Becke ldquoDensity-functional thermochemistry IIIThe roleof exact exchangerdquoThe Journal of Chemical Physics vol 98 no7 pp 5648ndash5652 1993

[32] C Lee W Yang and R G Parr ldquoDevelopment of the Colle-Salvetti correlation-energy formula into a functional of theelectron densityrdquo Physical Review B vol 37 no 2 pp 785ndash7891988

[33] H Yoshida K Takeda J Okamura A Ehara and H MatsuuraldquoA new approach to vibrational analysis of large molecules bydensity functional theory wavenumber-linear scalingmethodrdquoJournal of Physical Chemistry A vol 106 no 14 pp 3580ndash35862002

14 Organic Chemistry International

[34] H Yoshida A Ehara and H Matsuura ldquoDensity functionalvibrational analysis using wavenumber-linear scale factorsrdquoChemical Physics Letters vol 325 no 4 pp 477ndash483 2000

[35] M J Frisch G W Trucks H B Schlegel et al Gaussian 03Revision B 01 Gaussian Pittsburgh Pa USA 2003

[36] J M L Martin and C Van Alsenoy GAR2PED A Program toObtain a Potential Energy Distribution from a Gaussian ArchiveRecord University of Antwerp 2009

[37] P Pulay G Fogarasi F Pang and J E Boggs ldquoSystematicab initio gradient calculation of molecular geometries forceconstants and dipole moment derivativesrdquo Journal of theAmerican Chemical Society vol 101 no 10 pp 2550ndash2560 1979

[38] S Mishra D Chaturvedi N Kumar P Tandon and H WSiesler ldquoAn ab initio and DFT study of structure and vibrationalspectra of 120574 form of Oleic acid comparison to experimentaldatardquo Chemistry and Physics of Lipids vol 163 no 2 pp 207ndash217 2010

[39] W O George D V Hassid and W F Maddams ldquoConfor-mations of some 120572120573-unsaturated carbonyl compoundsmdashpartIII infrared solution spectra of methyl [2H3]methyl ethyland [2H5]ethyl acrylates and trans-crotonatesrdquo Journal of theChemical Society Perkin Transactions 2 no 4 pp 400ndash4041972

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

Page 13: Research Article Molecular Structure and Vibrational Spectra ...e molecular geometry, vibrational frequencies, and infrared intensities have been calculated by using density functional

Organic Chemistry International 13

References

[1] M Salkind E H Riddle and R W Keefer ldquoAcrylates andmethacrylates ester manufacture and marketsrdquo Industrial ampEngineering Chemistry Research vol 51 no 11 pp 1328ndash13341959

[2] K S Anseth S M Newman and C N Bowman ldquoPolymericdental composites properties and reaction behavior of multi-methacrylate dental restorationsrdquo Advances in Polymer Sciencevol 122 pp 176ndash217 1995

[3] J G Kloosterboer ldquoNetwork formation by chain crosslink-ing photopolymerization and its application in electronicsrdquoAdvances in Polymer Science vol 84 pp 1ndash61 1988

[4] K Matyjaszewski Y Gnanou and L Leibler MacromolecularEngineering vol 1 Wiley-VCH Weinheim Germany 2007

[5] M Orgill B L Baker and N L Owen ldquoFTIR studies ofconformational isomerism in acrylates and acrylic acidsrdquo Spec-trochimica Acta A vol 55 no 5 pp 1021ndash1024 1999

[6] M Salkind ldquoReaches into the marketrdquo Industrial amp EngineeringChemistry Research vol 56 pp 62ndash110 1964

[7] E Takacs K Dajka and L Wojnarovits ldquoStudy of high-energyradiation initiated polymerization of butyl acrylaterdquo RadiationPhysics and Chemistry vol 63 no 1 pp 41ndash44 2002

[8] H Yu J Peng M Zhai J Li G Wei and J Qiao ldquoRadiation-induced copolymerization of styrenen-butyl acrylate in thepresence of ultra-fine powdered styrene-butadiene rubberrdquoRadiation Physics and Chemistry vol 76 no 11-12 pp 1736ndash1740 2007

[9] P F Canamero J Luis de la Fuente and M Fermandez-GarcıaldquoCuring kinetic study using a well-controlled multifunctionalcopolymer based on glycidyl methacrylaterdquo European PolymerJournal vol 45 no 9 pp 2665ndash2673 2009

[10] DMathew C P ReghunadhanNair and K N Ninan ldquoPendantcyanate functional vinyl polymers and imidophenolic-triazinesthereof synthesis and thermal propertiesrdquo European PolymerJournal vol 36 no 6 pp 1195ndash1208 2000

[11] S Mitra S Chattopadhyay S Sabharwal and A K BhowmickldquoElectron beam crosslinked gels-Preparation characterizationand their effect on the mechanical dynamic mechanical andrheological properties of rubbersrdquoRadiation Physics and Chem-istry vol 79 no 2 pp 289ndash296 2010

[12] P Canamero-Martınez M Fermandez-Garcıa and J Luis de laFuente ldquoRheological cure characterization of a polyfunctionalepoxy acrylic resinrdquo Reactive and Functional Polymers vol 70no 10 pp 761ndash766 2010

[13] F Chu T McKenna and S Lu ldquoCuring kinetics of an acrylicresinepoxy resin system using dynamic scanning calorimetryrdquoEuropean Polymer Journal vol 33 no 6 pp 837ndash840 1997

[14] M C Douskey M S Gebhard A V McCormick et alldquoSpectroscopic studies of a novel cyclic oligomer with pendantalkoxysilane groupsrdquo Progress in Organic Coatings vol 45 no2-3 pp 145ndash157 2002

[15] R J Day P A Lovell and A A Wazzan ldquoToughened car-bonepoxy composites made by using coreshell particlesrdquoComposites Science andTechnology vol 61 no 1 pp 41ndash56 2001

[16] K Bolton D G Lister and J Sheridan ldquoRotational isomerismbarrier to internal rotation and electric dipole moment ofacrylic acid bymicrowave spectroscopyrdquo Journal of the ChemicalSociety Faraday Transactions 2 vol 70 pp 113ndash123 1974

[17] S W Charles F C Cullen N L Owen and G A WilliamsldquoInfrared spectrum and rotational isomerism of acrylic acidrdquoJournal of Molecular Structure vol 157 no 1ndash3 pp 17ndash25 1987

[18] K Bolton N L Owen and J Sheridan ldquoMicrowave spectra ofrotational isomers of acrylic acidrdquoNature vol 218 no 5138 pp266ndash267 1968

[19] G Williams N L Owen and J Sheridan ldquoSpectroscopicstudies of some substitutedmethyl formatesmdashpart 1microwavespectra and internal rotation barriers of methyl-fluoroformate-propiolate -cyanoformate -acrylate and -acetaterdquo Transac-tions of the Faraday Society vol 67 pp 922ndash949 1971

[20] T Tsuji H Ito H Takeuchi and S Konaka ldquoMolecularstructure and conformation ofmethylmethacrylate determinedby gas electron diffractionrdquo Journal of Molecular Structure vol475 no 1 pp 55ndash63 1999

[21] T Egawa S Maekawa H Fujiwara Takeuchi H Takeuchi andS Konaka ldquoMolecular structure and conformation of methylacrylate a gas electron diffraction study augmented by ab initiocalculation and rotational constantsrdquo Molecular Structure andSpectroscopy vol 352 pp 193ndash201 1995

[22] A Virdi V P Gupta and A Sharma ldquoAb initio studies onconformation vibrational and electronic spectra of methylmethacrylaterdquo Journal ofMolecular Structure vol 634 no 5 pp53ndash65 2003

[23] B L Baker M Orgill N L Owen et al ldquoThe molecularconformation of methyl methacrylatemdashan infrared and abinitio studyrdquo Journal of Molecular Structure vol 356 no 2 pp95ndash104 1995

[24] A N Mitra and I Santhanan ldquoRelativistic qqq spectra fromBethe-Salpeter premisesrdquo Physics Letters B vol 104 no 1 pp62ndash66 1981

[25] K Fan and J E Boggs ldquoRotational isomerism of acrylic acidrdquoJournal of Molecular Structure vol 157 no 1ndash3 pp 31ndash41 1987

[26] P Carmona and J Moreno ldquoThe infrared spectra and structureof methyl acrylaterdquo Journal of Molecular Structure vol 82 no3-4 pp 177ndash185 1982

[27] R J Loncharich T R Schwartz and K N Houk ldquoTheoreticalstudies of conformations of acrolein acrylic acid methyl acry-late and their Lewis acid complexesrdquo Journal of the AmericanChemical Society vol 109 no 1 pp 14ndash23 1987

[28] M Dulce G Faria J J C Teixeira-Dias and R FaustoldquoVibrational spectra and structure of methyl trans-crotonaterdquoVibrational Spectroscopy vol 2 no 2-3 pp 43ndash60 1991

[29] J J C Teixeira-Dias and R Fausto ldquoMolecular structure ofmethyl acrylate the high energy s-trans-(CO) conformerrdquoJournal of Molecular Structure vol 282 no 1-2 pp 123ndash1291993

[30] A J Bowles W O George and D B Cunliffe-Jones ldquoConfor-mations of some120572120573-unsaturated carbonyl compoundsmdashpart IIinfrared and Raman spectra of methyl and ethyl acrylates andtranscrotonatesrdquo Journal of the Chemical Society B pp 1070ndash1075 1970

[31] A D Becke ldquoDensity-functional thermochemistry IIIThe roleof exact exchangerdquoThe Journal of Chemical Physics vol 98 no7 pp 5648ndash5652 1993

[32] C Lee W Yang and R G Parr ldquoDevelopment of the Colle-Salvetti correlation-energy formula into a functional of theelectron densityrdquo Physical Review B vol 37 no 2 pp 785ndash7891988

[33] H Yoshida K Takeda J Okamura A Ehara and H MatsuuraldquoA new approach to vibrational analysis of large molecules bydensity functional theory wavenumber-linear scalingmethodrdquoJournal of Physical Chemistry A vol 106 no 14 pp 3580ndash35862002

14 Organic Chemistry International

[34] H Yoshida A Ehara and H Matsuura ldquoDensity functionalvibrational analysis using wavenumber-linear scale factorsrdquoChemical Physics Letters vol 325 no 4 pp 477ndash483 2000

[35] M J Frisch G W Trucks H B Schlegel et al Gaussian 03Revision B 01 Gaussian Pittsburgh Pa USA 2003

[36] J M L Martin and C Van Alsenoy GAR2PED A Program toObtain a Potential Energy Distribution from a Gaussian ArchiveRecord University of Antwerp 2009

[37] P Pulay G Fogarasi F Pang and J E Boggs ldquoSystematicab initio gradient calculation of molecular geometries forceconstants and dipole moment derivativesrdquo Journal of theAmerican Chemical Society vol 101 no 10 pp 2550ndash2560 1979

[38] S Mishra D Chaturvedi N Kumar P Tandon and H WSiesler ldquoAn ab initio and DFT study of structure and vibrationalspectra of 120574 form of Oleic acid comparison to experimentaldatardquo Chemistry and Physics of Lipids vol 163 no 2 pp 207ndash217 2010

[39] W O George D V Hassid and W F Maddams ldquoConfor-mations of some 120572120573-unsaturated carbonyl compoundsmdashpartIII infrared solution spectra of methyl [2H3]methyl ethyland [2H5]ethyl acrylates and trans-crotonatesrdquo Journal of theChemical Society Perkin Transactions 2 no 4 pp 400ndash4041972

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

Page 14: Research Article Molecular Structure and Vibrational Spectra ...e molecular geometry, vibrational frequencies, and infrared intensities have been calculated by using density functional

14 Organic Chemistry International

[34] H Yoshida A Ehara and H Matsuura ldquoDensity functionalvibrational analysis using wavenumber-linear scale factorsrdquoChemical Physics Letters vol 325 no 4 pp 477ndash483 2000

[35] M J Frisch G W Trucks H B Schlegel et al Gaussian 03Revision B 01 Gaussian Pittsburgh Pa USA 2003

[36] J M L Martin and C Van Alsenoy GAR2PED A Program toObtain a Potential Energy Distribution from a Gaussian ArchiveRecord University of Antwerp 2009

[37] P Pulay G Fogarasi F Pang and J E Boggs ldquoSystematicab initio gradient calculation of molecular geometries forceconstants and dipole moment derivativesrdquo Journal of theAmerican Chemical Society vol 101 no 10 pp 2550ndash2560 1979

[38] S Mishra D Chaturvedi N Kumar P Tandon and H WSiesler ldquoAn ab initio and DFT study of structure and vibrationalspectra of 120574 form of Oleic acid comparison to experimentaldatardquo Chemistry and Physics of Lipids vol 163 no 2 pp 207ndash217 2010

[39] W O George D V Hassid and W F Maddams ldquoConfor-mations of some 120572120573-unsaturated carbonyl compoundsmdashpartIII infrared solution spectra of methyl [2H3]methyl ethyland [2H5]ethyl acrylates and trans-crotonatesrdquo Journal of theChemical Society Perkin Transactions 2 no 4 pp 400ndash4041972

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

Page 15: Research Article Molecular Structure and Vibrational Spectra ...e molecular geometry, vibrational frequencies, and infrared intensities have been calculated by using density functional

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of


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ANTIFUNGAL ACTIVITY AND MOLECULAR IDENTIFICATION OF …

Molecular recognition of organic ammonium ions in solution ... · the inspiration for supramolecular research, including self-assembly, mechanically-interlocked molecular architectures

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Ginger (Zingiber officinale) phytochemicals—gingerenone-A and …bio.gnu.ac.kr/publication/pdf/2018_03(154).pdf · 2018-04-30 · inhibit SaHPPK: molecular docking, molecular dynamics

Pulmonary Tuberculosis and Mycobacterium Tuberculosis Modern Molecular … · 2020-03-05 · CHAPTER 1 Pulmonary Tuberculosis and Mycobacterium Tuberculosis: Modern Molecular Epidemiology

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Study of Molecular Interactions and Surface Alignment

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Biophotonics applications of nanometric apertures · biotechnology. Applications range from molecular diagnostics to DNA sequencing and screening for rare molecular types Eigen and

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Introduction to Molecular Biology

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Fast Molecular Compression by a Hyperthermal Collision Gives Bond … · 2020-07-10 · KRUMBEIN et al. - FAST MOLECULAR COMPRESSION BY HYPERTHERMAL COLLISION 1 Fast Molecular Compression

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Dr Siti Suri Lecture 7 Molecular Techniques

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Molecular analysis of translocations associated with Ewing

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Rational molecular passivation for high-performance ...liu.diva-portal.org/smash/get/diva2:1327434/FULLTEXT01.pdf · 1 Rational molecular passivation for high-performance perovskite

Synthesis, molecular dynamics simulation and adsorption

Molecular Portraits of Epithelial, Mesenchymal, and Hybrid ...€¦ · Integrated Systems and Technologies Molecular Portraits of Epithelial, Mesenchymal, and Hybrid States in Lung

COMPUTATIONAL INVESTIGATIONS OF MOLECULAR COMPLEXES OF BIOTECHNOLOGICAL INTEREST · 2014-04-30 · COMPUTATIONAL INVESTIGATIONS OF MOLECULAR COMPLEXES OF BIOTECHNOLOGICAL INTEREST

IEEE TRANSACTIONS ON COMMUNICATIONS 1 Molecular …

Identification, expression analysis and molecular modeling ... · Identification, expression analysis and molecular modeling of Iron deficiency specific clone 3 (Ids3) like gene in

Isolation and Molecular Characterization of Novel

Molecular classification of gastric cancer: Towards a ... · Molecular classification of gastric cancer: Towards a pathway- driven targeted therapy Ismael Riquelme 1,* , Kathleen

Molecular phylogenetic relationships of Lankanectes corrugatus … · 2005. 5. 20. · Molecular phylogenetic relationships of Lankanectes corrugatus from Sri Lanka: endemism of South

Molecular dynamics simulation of uni and bi-modal … · 2019-10-18 · 4.2 Modeling systems ... First of all, the crystallization behavior and the molecular topology of bimodal molecular

1 Dynamique moléculaire ( Molecular dynamics MD )

Nonadiabatic Molecular Dynamics Simulations of the Energy ...cnls.lanl.gov/~serg/postscript/jp900904q.pdf · Nonadiabatic Molecular Dynamics Simulations of the Energy Transfer between

Computational Design of Intrinsic Molecular Rectifiers ...ursula.chem.yale.edu/~batista/publications/rect_2015.pdf · Computational Design of Intrinsic Molecular Rectifiers Based