Desilylation of β-silyl pyridinium ions: Gas-phase and solution-phase studies in conjunction with DFT calculations

Abstract

Gas-phase chemistry of N-methyl 2- and 4-trimethylsilylmethylpyridinium ions 8 and 20 and the deuterated derivatives 17 and 21 was investigated using electrospray ionization (ESI) and tandem mass spectrometry. Collision-induced ionization (CID) of the derived ions m/z 180 from both 8 and 20 gave rise to (CH3)3Si+ at m/z 73 in addition to ions at m/z 108 and 106 arising from competing proton transfer and hydride transfer pathways from within the initially formed ion-molecule complexes. CID of the derived ions m/z 189 from the deuterated derivatives 17 and 21 gave rise to (CD 3)3Si+ at m/z 82, in addition to ions at m/z 109 and 106. Formation of the m/z 108 ions from 8 and 20 provides evidence..