Isomerisation of phosphabutyne and a photochemical route to phosphabutadiyne (HC3P), a phosphorus analogue of cyanoacetylene

Abstract

The photochemistry of phosphabut-1-yne, CH₃CH₂CP, was investigated by means of infrared spectroscopy assisted by theoretical (DFT) predictions. The UV-irradiated compound, isolated in a cryogenic argon matrix, undergoes isomerization and dissociation. Several isomers of phosphabutyne, in addition to phosphabutadiyne (HC₃P), ethynylphosphinidene (HCCP), and phoshaethyne (HCP) are formed as the main photoproducts. Vibrational spectra of astrochemically relevant molecules HC₃P and CH₂CHCP (vinylphosphaethyne), have been detected and analyzed here for the first time.