Metastable ion study of organosilicon compounds. Part I—Diethoxydimethylsilane

Electron impact induced fragmentations of diethoxydimethylsilane (1) and its deuterium-labelled analogues (2 and 3) were investigated by mass-analysed ion kinetic energy spectrometry. The principal fragmentation processes of compound 1 are dominated by silicenium ions which undergo consecutive losses of ethylene and aldehyde molecules. The fragmentations of 1 led to the formation of protonated silanoic acid [CH3Si(OH)2]+ and protonated dimethyl-silanone [(CH3)2Si = OH]+, and their unimolecular reacdvities were clarified. The fragmentation characteristics of compound 1 are compared with those of the carbon analogue, acetone diethyl acetal (4).