Research Article
Molecular Structure and Vibrational Spectra of 2-Ethylhexyl Acrylate by Density Functional Theory Calculations
Table 1
Optimized geometries of s-cis and s-trans 2-ethylhexyl acrylate conformations by DFT//B3LYP/6-311+G**.
| Internal coordinates | Level of theory DFT/6-311+G** s-cis EHA | s-cis methyl acrylatea | DFT/6-311+G** s-trans EHA | s-trans methyl acrylateb |
| Bond lengths () | | | | | C1H2 | 1.084 | | 1.083 | 1.074 | C1H3 | 1.083 | | 1.084 | 1.075 | C1C4 | 1.331 | 1.341(7) | 1.332 | 1.319 | C4H5 | 1.084 | | 1.084 | 1.075 | C4C6 | 1.486 | 1.484(6) | 1.484 | 1.484 | C6O7 | 1.210 | 1.211(2) | 1.211 | 1.191 | C6O8 | 1.351 | 1.349(3) | 1.348 | 1.325 | O8C9 | 1.448 | 1.439(3) | 1.448 | 1.417 | C9H10 | 1.093 | | 1.093 | | C9H11 | 1.093 | | 1.092 | | C9C12 | 1.526 | | 1.526 | | C12H13 | 1.098 | | 1.098 | | C12C14 | 1.543 | | 1.543 | | C14H15 | 1.097 | | 1.097 | | C14H16 | 1.096 | | 1.096 | | C14C17 | 1.531 | | 1.531 | | C17C18 | 1.094 | | 1.094 | | C17H19 | 1.093 | | 1.093 | | C17H20 | 1.092 | | 1.092 | | C12C21 | 1.549 | | 1.549 | | C21H22 | 1.097 | | 1.097 | | C21H23 | 1.094 | | 1.094 | | C21C24 | 1.534 | | 1.534 | | C24H25 | 1.097 | | 1.097 | | C24H26 | 1.095 | | 1.095 | | C24C27 | 1.533 | | 1.533 | | C27H28 | 1.097 | | 1.097 | | C27H29 | 1.097 | | 1.096 | | C27C30 | 1.531 | | 1.531 | | C30H31 | 1.094 | | 1.093 | | C30H32 | 1.094 | | 1.094 | | C30H33 | 1.094 | | 1.094 | | Bond angles (°) | | | | | H2C1H3 | 118.049 | | 117.591 | | H2C1C4 | 120.479 | | 121.432 | 121.7 | C1C4H5 | 122.220 | | 121.739 | 122.1 | C1C4C6 | 121.072 | 120.3(8) | 124.970 | 124.2 | C4C6O7 | 125.710 | 126.1(5) | 123.066 | 122.9 | C4C6O8 | 110.564 | 110.3(3) | 113.320 | 113.7 | C6O8C9 | 116.570 | 116.4(5) | 116.493 | 116.8 | O8C9H10 | 108.658 | | 108.697 | | O8C9H11 | 108.313 | | 108.339 | | O8C9C12 | 108.522 | | 108.488 | | C9 C12C14 | 108.099 | | 108.115 | | C12C14H15 | 108.729 | | 108.720 | | C12C14H16 | 108.539 | | 108.544 | | C12C14C17 | 115.410 | | 115.400 | | C14C17H18 | 111.304 | | 111.345 | | C14C17H19 | 110.477 | | 110.478 | | C14C17H20 | 112.028 | | 112.001 | | C9C12C21 | 111.382 | | 111.384 | | C12C21H22 | 109.228 | | 109.231 | | C12C21H23 | 109.005 | | 109.019 | | C12C21C24 | 114.775 | | 114.824 | | C21C24H25 | 108.695 | | 108.731 | | C21C24H26 | 110.286 | | 110.291 | | C21C24C27 | 113.287 | | 113.308 | | C24C27H28 | 109.207 | | 109.229 | | C24C27H29 | 109.217 | | 109.208 | | C24C27C30 | 113.280 | | 109.208 | | C27C30H31 | 111.428 | | 111.428 | | C27C30H32 | 111.218 | | 111.209 | | C27C30H33 | 111.189 | | 111.202 | | Dihedral angles (°) | | | | | H3H2C1C4 | 180 | | −179.908 | | H2C1C4H5 | −179.977 | | 179.808 | | H2C1C4C6 | 0.037 | | 0.106 | | C1C4C6O7 | −0.166 | | 178.652 | | C1C4C6O8 | 179.844 | | −1.298 | | C4C6O8C9 | 179.896 | | 179.515 | | C6O8C9H10 | 55.606 | | 55.506 | | C6O8C9H11 | −61.282 | | −61.454 | | C6O8C9C12 | 177.303 | | 177.169 | | O8C9 C12H13 | 55.024 | | 54.463 | | O8C9C12C14 | 171.114 | | 170.547 | | C9C12C14H15 | 61.844 | | 61.568 | | C9C12C14H16 | −53.102 | | −53.378 | | C9C12C14C17 | −175.215 | | −175.516 | | C12C14C17H18 | 56.957 | | 57.249 | | C12C14C17H19 | 176.491 | | 176.782 | | C12C14C17H20 | −63.865 | | −63.596 | | O8C9C12C21 | −63.322 | | −63.915 | | C9C12C21H22 | −96.883 | | −97.147 | | C9C12C21H23 | 18.587 | | 18.279 | | C9C12C21C24 | 139.536 | | 139.298 | | C12C21C24H25 | −59.615 | | −59.061 | | C12C21C24H26 | 56.214 | | 56.717 | | C12C21C24C27 | 178.823 | | 179.360 | | C21C24C27H28 | −58.771 | | −58.768 | | C21C24C27H29 | 56.758 | | 56.753 | | C21C24C27C30 | 179.033 | | 179.029 | | C24C27C30H31 | 179.693 | | −179.983 | | C24C27C30H32 | −60.205 | | −59.888 | | C24C27C30H33 | 59.599 | | 59.917 | |
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aDetermined by a joint analysis of electron diffraction data and rotational constants [21].
bDetermined by ab initio calculation at HF/6–31G** [20].
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