Mass spectra of vinyltriphenyl derivatives of fourth main-group elements

The electron-impact induced fragmentation of vinyltriphenyl derivatives of carbon, silicon, germanium, and tin has been studied at 70 eV under high resolution. The fragmentation modes of the germanium and tin compounds are assigned mainly on the basis of the known^1,2 decomposition of Ph₃Ge⁺ and Ph₃Sn⁺, respectively. The behaviour of vinyltriphenylsilane on electron impact is nearer to the organic member of the series than to the organometallic members. Unique features in the series are the observation of tropylium ion in the spectrum of 1,1,1-triphenylpropene, and transitions in the spectrum of the latter in which methyl radicals are eliminated; a possible mechanism of formation of tropylium ion is suggested. © 1968.