A comparison of the electron impact and fast atom bombardment mass spectra of some group IV organometallic halides

Abstract

The positive ion fast atom bombardment (FAB) mass spectra of a series of group IV organometallic halides, (phenyl)3MCl (M = Ge, Sn, Pb), (phenyl)3PbX (X = Cl, Br, I) and Sn(phenyl)nCl4−n are reported in a sulfolane matrix, and compared to their corresponding EI spectra. The use of other matrix liquids such as glycerol thioglycerol, diamylphenol, 18-crown-6/tetraglyme, and p-nitrophenyloctylether are discussed. Disappointingly FAB, like EI, does not produce significant parent ions for group IV organometallics. The FAB and EI spectra are remarkably similar with one major exception. In EI, the loss of a phenyl is preferred over the loss of a halide, while in FAB the reverse is the case, strongly suggesting that the primary ionization occurs in the condensed phase.