Vibrational Spectra and Conformations of 2,2,2-Trifluoroethylamine and 2,2,2-Trifluoroethanol

Article abstract of DOI:10.1021/j100452a015

The infrared and Raman spectra of 2,2,2-trifluoroethylamine (CF3CH2NH2) and 2,2,2-trifluoroethanol (CF3CH2OH) have been recorded in the fluid and solid phases.For CF3CH2NH2, the C-C stretch and the -NH2 stretch appear as doublets as a result of the equilibrium mixture of trans and gauche conformers.A value for ΔH of 2.9 kcal/mol has been determinated from a variable temperature study for the gas phase, and the -NH2 torsion for the more stable trans conformer has been observed at 264 cm^-1.The Δv=2 transitions for the -CF3 torsion have been observed, and the derived barrier to internal rotation is 3.85+/-0.06 kcal/mol.Microwave transitions for two excited vibrational states have also been assigned for trans-2,2,2-trifluoroethylamine.A similar equilibrium between two conformers exists for CF3CH2OH.The -OH and -OD torsions for the more stable gauche conformer have been observed in the far-infrared spectra.The value of the -CF3 barrier has been calculated to be 3.72+/-0.15 kcal/mol.