Characterization of ionized heterocyclic carbenes by ion-molecule reactions

1,2-Hydrogen shift isomers of ionized pyridine, thiazole and imidazole are readily characterized by the study of their associative ion-molecule reacti ons with dimethyl disulfide in the quadrupole collision cell of a new hybri d sector-quadrupole-sector mass spectrometer, Efficient trapping reactions of CH3S. radicals are indeed observed and the actual structure of the adduc t [M + CH3S](+) ions is clearly indicated by their high-energy collisional activation mass spectra, These trapping reactions are not observed for the 'conventional' pyridine, thiazole and imidazole molecular ions, which only react by charge exchange producing m/z 94, [CH3SSCH3](.+), ions. Copyright (C) 1999 John Wiley & Sons, Ltd.