Premium
Spectra and structure of organophosphorus compounds XXXVIII —Raman and infrared spectra, vibrational assignment, conformational stability and normal coordinate analysis for ethylphosphonic dichloride
Author(s) -
Durig J. R.,
James C. G.,
Hizer T. J.
Publication year - 1990
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.1250210302
Subject(s) - conformational isomerism , raman spectroscopy , chemistry , infrared , enthalpy , molecule , infrared spectroscopy , spectral line , valence (chemistry) , analytical chemistry (journal) , crystallography , organic chemistry , thermodynamics , physics , astronomy , optics
The Raman (3500‐10 cm −1 ) and infrared (3500‐50 cm −1 ) spectra of solid CH 3 CH 2 P(O)Cl 2 and CD 3 CD 2 P(O)Cl 2 and the infrared spectra of the gases were recorded. Additionally, the Raman spectra of the liquids were measured and qualitative depolarization ratios were obtained. Since several distinct Raman lines disappear from the spectra on going from the fluid to the solid states, it is concluded that the molecule exists as a mixture of trans and gauche conformers. A variable‐temperature study of the Raman spectrum of the liquid yielded an enthalpy difference between the conformers of 72 ± 10 cm −1 (206 ± 27 cal mol −1 ). The trans conformer is the more stable form in the liquid, and the only one present in the solid. On the basis of band intensities, group frequencies and depolarization values, a complete vibrational assignment is proposed for the trans conformer. This assignment is supported by a normal coordinate analysis utilizing a modified valence force field. These results are compared with those from some similar molecules.