Infrared and Raman Investigation of Condensed Phases of Methylamine and Its Deuterium Derivatives

The infrared spectra of solid and matrix-isolated methylamine, methylamine-d2, methyl-d3-amine, and methyl-d3-amine-d2 have been recorded from 4000 to 250 cm−1. The Raman spectra of the four isotopic species have also been recorded and depolarization values measured. The elusive NH2 twisting vibration has been located in the solid-phase infrared spectra of CH3NH2 and CD3NH2, and the assignment is in agreement with both the product rule and earlier assignments for this normal mode in hydrazine. A temperature-dependent hydrogen-bonding study has been carried out and ΔH° for H-bond formation in methylamine-d2 was found to be −660 cal/mole.