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Experimental and theoretical structure and vibrational analysis of ethyl trifluoroacetate, CF 3 CO 2 CH 2 CH 3
Author(s) -
Defonsi Lestard María Eliana,
Tuttolomondo María Eugenia,
Wann Derek A.,
Robertson Heather E.,
Rankin David W. H.,
Altabef Aida Ben
Publication year - 2010
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.2550
Subject(s) - conformational isomerism , raman spectroscopy , chemistry , infrared spectroscopy , ab initio , infrared , crystallography , ab initio quantum chemistry methods , electron diffraction , density functional theory , natural bond orbital , computational chemistry , diffraction , molecule , organic chemistry , physics , optics
The molecular structure and conformational properties of ethyl trifluoroacetate, CF 3 CO 2 CH 2 CH 3 , were determined in the gas phase by electron diffraction, and vibrational spectroscopy (IR and Raman). The experimental investigations were supplemented by ab initio (MP2) and DFT quantum chemical calculations at different levels of theory. Experimental and theoretical methods result in two structures with C s ( anti–anti ) and C 1 ( anti–gauche ) symmetries, the former being slightly more stable than the latter. The electron‐diffraction data are best fitted with a mixture of 56% anti–gauche and 44% anti–anti conformers. The conformational preference was also studied using the total energy scheme, and the natural bond orbital scheme. Also, the infrared spectra of CF 3 CO 2 CH 2 CH 3 are reported for the gas, liquid and solid states, as is the Raman spectrum of the liquid. The comparison of experimental averaged IR spectra of C s and C 1 conformers provides evidence for the predicted conformations in the IR spectra. Harmonic vibrational wavenumbers and scaled force fields have been calculated for both conformers. Copyright © 2009 John Wiley & Sons, Ltd.