Ion Chemistry of Phosphirane and Structure of the Phosphirane Molecular Ion

Abstract

The mass spectrum and the ion molecule reactions of phosphirane and of mixtures of phosphirane with NH 3 , NH 2 D, NHD 2 and ND 3 have been studied by ion cyclotron resonance spectrometry. Almost all important product ions are formed by PH-group transfer reactions, where ethene is generated as the neutral particle. Only two of the more abundant ions, the protonated molecule, H 2 P(CH 2 ) 2 + and the ion m/e=63, P 2 H + , are formed via other reaction pathways. Secondary, tertiary and quarternary product ions with the general formula R(PH) n + (R: phosphirane fragment, n-1, 2, 3) have been detected. The molecular ion is proved to have a cyclic structure. Two possible structures of the product ions with two and three phosphorus atoms are discussed: a structure with an open phosphorus chain, leaving the phosphirane ring intact and a ring extended structure, produced by a ring extension reaction of the PH-group. Several rate constants of the ion molecule reactions of the phosphirane molecular ion are given