Thermochemical properties and gas-phase ion chemistry of phenylsilane investigated by FT-ICR spectrometry. Identification of parent- and fragment-ion structural isomers by their specific reactivities

Loss of benzene from methylphenylsilane and dimethylphenylsilane molecular cations

“…The dissociation of phenylsilane (1a) molecular cation is a good example [2][3][4][5][6][7][8][9]. As it is well known, the tropylium ion is produced from the toluene molecular cation as well as the benzylium ion [10][11][12][13].…”

Collision‐induced dissociation of the phenylsilane molecular ion

“…However, for the unreactive isomer that does not undergo the ion‐molecule reaction, controversy still remains. Beauchamp and coworkers suggested the silacycloheptatrienyl ( 3 ) structure for the unreactive [MH] + ion,5 the silicon analogue of the tropylium ion. In the later quantum chemical calculation studies6–8 it was shown that 3 is less stable than 2 , and its production was ruled out.…”

“…The dissociation of organosilicon ions has been studied extensively over the years 1–11. Comparison of their dissociation properties with those of their carbon analogues has been an interesting subject in mass spectrometric studies.…”

“…have been limited 2–9. Even though it was studied in the early days of mass spectrometry,2,3 it had not received much attention since then, until a recent study of ion‐molecule reactions using ion cyclotron resonance spectrometry by Beauchamp and coworkers 4,5. It was found that the [MH] + ion is produced in two isomeric forms, non‐interconverting at room temperature, by electron ionization (EI) of phenylsilane.…”

Gas‐Phase Ion Chemistry of Silicon‐Containing Molecules†This article is dedicated to Saul Patai.

“…Thus, Beauchamp and coworkers 244,245 have found that electron ionization of phenylsilane gives rise to both isomers 85 and 86, which do not interconvert at room temperature and can be readily distinguished by their ion molecule reactions. …”