Spectra and structure of organophosphorus compounds: XVII. Infrared and Raman spectra. vibrational assignment and barriers to internal rotation for t-butylphosphine

Abstract

The infrared spectra of gaseous and solid tertiary-butylphosphine, [(CH 3) 3CPH 2], have been recorded from 50 cm −1 to 3500 cm −1. The Raman spectra of gaseous, liquid and solid (CH 3) 3CPH 2 have been recorded from 10 to 3500 cm −1. A vibrational assignment of the 42 normal modes has been made. A harmonic approximation of the methyl torsional barrier from observed transitions in the solid state gave a result of 4.22 kcal mol −1 and 3.81 kcal mol −1 in the gaseous state. Hot band transitions for the phosphino torsional mode have been observed. The potential function for internal rotation about the C-P bond has been calculated. The two potential constants were determined to be: V 3 = 2.79 ± 0.01 kcal mol −1 and V 6 = 0.07 ± 0.01 kcal mol −1.