IR and Raman spectra, force fields, barrier heights and thermodynamic functions for isomeric trifluoromethyl anilines

Abstract

Raman spectra (50-4000 cm-1) together with depolarization ratio measurements and IR spectra (180-4000 cm-1) of isomeric trifluoromethylanilines were recorded. Vibrational assignments for the observed wavenumber were made assuming C, symmetry for all the molecules. Using the thus assigned fundamentals and assumed structural parameters, general valence force fields were determined. Consistent assignments for the internal modes of the CF3 and NH2 groups are proposed and the substituent-sensitive phenyl-ring modes are discussed. Barriers to internal rotations for the CF3 and NH2 tops were determined using the single top theory. The thermodynamic functions were also computed.