Molecular structure, conformation, vibrational and electronic spectra of methyl trans crotonate

Virdi, Ajit; Gupta, Vikram; Sharma, Atul

doi:10.1016/j.theochem.2004.02.046

Cited by 4 publications

(9 citation statements)

References 14 publications

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“…No experimental data for the ionization potentials seem to have been reported in the literature. However, the RHF values are close to those reported for analogous molecule methyl trans crotonate by HAM/3 calculation (9.82 eV) by Buemi et al [19] and by RHF calculations (10.22 ± 0.08 eV) by Virdi et al [9]. No appreciable change is found in the ionization potential of MMP on transition from S 0 to S 1 state.…”

Section: Conformational Studiessupporting

confidence: 88%

“…A comparison of the S 0 state geometries of identical conformers of MMP and methyl trans crotonate reported by Virdi et al [9], shows that the replacement of the methyl group by a methoxy group does not change molecular geometry appreciably.…”

Section: Optimized Geometriesmentioning

confidence: 87%

“…1) were obtained for the E-isomer. Our earlier studies on methyl acrylate [7] and methyl trans crotonate [9], show that the C=O and O-CH 3 groups in the esters have a s-cis orientation. It was, therefore, attempted to find the orientation of the second methoxy group of MMP relative to the C=C bond to which it is connected through C 3 -O 8 bond.…”

Section: Methods Of Calculationmentioning

confidence: 99%

“…Baker et al [13] have suggested certain scaling factors for RHF frequencies. These have been used in the present case with certain modifications based on our experience with unsaturated ester molecules [8,9]. Thus, scaling factors for single bonded torsion and X-X-X bend (X refers to non-hydrogen atoms) have been taken as 0.905 and 0.912, respectively, as against 0.913 and 0.990 suggested by Baker et al [13].…”

Section: Vibrational Analysismentioning

confidence: 99%

“…Some such studies on a series of compounds like methyl acrylate [7], methyl methacrylate [8], and methyl trans crotonate [9], which are two rotor systems, having the possibility of rotational isomerism about C-O and C-C single bonds, have been undertaken in this laboratory using spectroscopic and quantum chemical techniques. In contrast to these molecules, methyl-3-methoxy-2-propenoate (MMP) has the possibility of rotational isomerism about three bonds (two C-O and one C-C) and may have a more complex structure.…”

Section: Introductionmentioning

confidence: 99%

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Theoretical study of structure, vibrational and electronic spectra of isomers of methyl-3-methoxy-2-propenoate

2004

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Abstract:A systematic quantum mechanical study of the possible conformations, their relative stabilities, vibrational and electronic spectra and thermodynamic parameters of methyl-3-methoxy-2-propenoate has been reported for the electronic ground (S 0 ) and first excited (S 1 ) states using time-dependent and time-independent Density Functional Theory (DFT) and RHF methods in extended basis sets. Detailed studies have been restricted to the E-isomer, which is found to be substantially more stable than the Z-isomer. Four possible conformers c Cc, c Tc, t Cc, t Tc, of which the first two are most stable, have been identified in the S 0 and S 1 states. Electronic excitation to S 1 state is accompanied with a reversal in the relative stability of the c Cc and c Tc conformers and a substantial reduction in the rotational barrier between them, as compared with the S 0 state. Optimized geometries of these conformers in the S 0 and S 1 states are being reported. Based on suitably scaled RHF/6-31G** and DFT/6-311G** calculations, assignments have been provided to the fundamental vibrational bands of both these conformers in terms of frequency, form and intensity of vibrations and potential energy distribution across the symmetry coordinates in the S 0 state. A complete interpretation of the electronic spectra of the conformers has been provided.

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Section: Conformational Studiessupporting

confidence: 88%

Section: Optimized Geometriesmentioning

confidence: 87%

Section: Methods Of Calculationmentioning

confidence: 99%