Vibrational spectra, barriers to internal rotation and conformation of propargyl methyl ether and methoxyacetonitrile

Abstract

The infra-red absorption spectra of propargyl methyl ether and the isoelectronic compound methoxyacetonitrile in the vapour, liquid and solid states have been examined. The spectra of both ethers indicate the presence of a conformational equilibrium of trans and gauche forms, the latter being the more stable in both cases. Calculations of the magnitude of the barrier to rotation of the methyl group and of the barrier to rotation about the O—CH₂X bond have been made for the gauche rotamer of both compounds.