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Conformational equilibria for 3‐methylstyrene: Raman and FTIR spectra and ab initio calculations
Author(s) -
Meurisse I.,
RibeiroClaro P. J. A.,
TeixeiraDias J. J. C.,
Pouchan C.
Publication year - 1995
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.1250261203
Subject(s) - conformational isomerism , raman spectroscopy , ab initio , chemistry , ab initio quantum chemistry methods , spectral line , phase (matter) , computational chemistry , liquid phase , crystallography , thermodynamics , molecule , organic chemistry , physics , astronomy , optics
The Raman spectra of liquid 3‐methylstyrene show pairs of bands whose temperature‐dependent intensities clearly suggest the occurrence of a conformational equilibrium. From these bands, assigned to cis and trans conformers, a trans‐cis energy difference of 0.8 + 0.2 kJ mol −1 was obtained for the liquid phase. On the other hand, ab initio calculations at the 3‐21G ** and MP2/3‐21G* levels predict a cis form more stable than the trans form by less than 0.15 kJ mol −1 , in good agreement with gas‐phase literature results.