Hydrogen Bonding in Gaseous Mixtures: Amine–Alcohol Systems

Abstract

Millen and Zabicky¹ have recently reported the infrared detection of hydrogen bonding in gaseous mixtures of methanol and methylamines. The strongest complex appears to be formed with trimethylamine, and the OH stretching band, displaced to 3,350 cm⁻¹, shows pronounced shoulders at 3,495 cm⁻¹ and 3,200 cm⁻¹. These have been interpreted by Millen and Zabicky as the sum and difference combinations of 3,350 cm⁻¹ with the stretching of the H-bond itself, implying a frequency for the latter of about 140 cm⁻¹. An alternative explanation of the shoulder on the high-frequency side is that it is due to a weak band associated with the trimethylamine part of the complex, intensified by Fermi resonance with the 3,350 cm⁻¹ band. At Dr. Millen's suggestion we have examined the far infra-red absorption of gaseous methanol–amine mixtures, in an attempt to distinguish between these two possibilities.