Metastable ion study of organosilicon compounds VIII. Dimethoxydiphenylsilane

Abstract

The spontaneous unimolecular dissociation reaction of the molecular ion of dimethoxydiphenylsilane ( 1) has been investigated by mass-analyzed ion kinetic energy spectroscopy, collision-induced dissociation, a D-labeling study and high resolution data. The results are compared with those of the corresponding carbon analogue, dimethoxydiphenylmethane ( 2). The fragmentation of the metastable 1 .+ is more complex than that of 2 .+. The latter eliminates the methoxy radical only, whereas the former eliminates methanol and benzene molecules, and C 7H 7 radical in addition to the formation of the molecular ion of biphenyl ( 3). The intensity of the [MC 6H 5] + ion at m/ z = 167 is much larger than that of [MOCH 3] + ion at m/ z = 213 in the normal mass spectrum of 1. On the contrary, in the case of 2, the intensity of [MC 6H 5] + ions is smaller than that of [MOCH 3] 3+ ions.