Unimolecular Gas-phase Reactions of Organosilicon Compounds. Part XV. Acetyltrimethylsilane, CH₃COSi(CH₃)₃

Abstract

Unimolecular metastable ion decompositions of acetyltrimethyl silane, CH₃COSi(CH₃)₃ (MW: 116, (1)) generated by electron ionization, have been investigated by use of mass-analyzed ion kinetic energy (MIKE) spectrometry and D-labeling. In the metastable time window, the molecular ions 1^{+ •} decompose exclusively into the ions at m/z 101, [M-CH₃]⁺. A considerable extent of H/D exchange occurs prior to this [M-CH₃]⁺ formation. However, the H/D exchange is hardly observed for the [M-CH₃]⁺ formation in the ion source. The generated m/z 101 ions from 1^{+ •} consist of two isomeric ions. A trimethylsilyl ion, (CH₃)₃Si⁺, at m/z 73 is generated by at least three different routes.