Metastable ion study of organosilicon compounds. Part III—trimethoxyphenylsilane

Abstract

Abstract The unimolecular decomposition of trimethoxyphenylsilane (1) was investigated by mass‐analysed ion kinetic energy (MIKE) spectrometry, deuterium‐labelling studies and from high resolution data. The characteristic fragmentations of metastable molecular ion of 1 were losses of C 6 H 6 and C 7 H 7 · with rearrangements. Almost complete H/D scrambling occurred in the molecular ion prior to these decompositions. The other important fragmentation routes corresponded to expulsions of CH 3 O · and C 6 H 5 · . These fragmentations were followed by consecutive elimination of an H 2 CO molecule, as commonly observed in the mass spectra of alkoxysilanes. In these fragmentation processes, H/D scrambling increased as the internal energy of the molecular ion was lowered. The fragmentations of 1 were compared with those of its carbon analogue, α,α,α‐trimethoxytoluene.