Heteroarylsilyl cations elaborated from a quinoline skeleton have been prepared from the corresponding silanes, and their structures were studied by 1H, 29Si, and 15N NMR. DOSY experiments and DFT calculations were also carried out which showed that the silyl cation center is stabilized intramolecularly by the quinoline nitrogen atom (N1), forming a highly strained and quasi planar 4-membered ring. Oxygenated and nitrogenated substituents at the C4 position on the quinoline ring were shown to reinforce the Si−N1 interaction through a p-π conjugation. The Lewis acidity of this class of silylium was finally determined using Müller's nitrilium method.

Reduction of phosphine oxides into the corresponding phosphines using PhSiH3 as a reducing agent and Ph3C+[B(C6F5)4]− as an initiator is described. The process is highly efficient, reducing a broad range of secondary and tertiary alkyl and arylphosphines, bearing various functional groups in generally good yields. The reaction is believed to proceed through the generation of a silyl cation, which reaction with the phosphine oxide provides a phosphonium salt, further reduced by the silane to afford the desired phosphine along with siloxanes.

Pyridine- and quinoline-stabilized silyl cations have been prepared, and their structure in condensed phases unambiguously assigned using 1H, 13C, 15N, 29Si, and 1H DOSY NMR as well as X-ray diffraction studies. Solid state structures thus show in both cases a stabilization of the cationic silicon center through an N-Si interaction and formation of a highly strained four-membered ring system. Chiral memory at the silicon atom in these heterocycle-stabilized silyl cations was also established, leading to various levels of selectivity depending on the nature of the heterocycle. Lowest energy conformations of the starting silanes obtained through DFT calculations, along with the isolation and characterization of the Si-centered chiral silyl cation intermediates, finally allowed to propose a plausible hypothesis as to the configurational stability of these silyl cations.