A Route to Base Coordinate Silicon Difluoride and the Silicon Trifluoride Radical.

Silicon difluoride (SiF2 ) is highly unstable at room temperature and condenses at this temperature rapidly to a polymeric material of unknown structure. Therefore, the isolation of a stable monomeric silicon difluoride species is a challenging task. The cyclic alkyl(amino) carbene (cAAC) coordinated silicon difluoride was isolated as (cAAC)2 SiF2 (2), synthesized from the reduction of cAAC-SiF4 (1) by using two equivalents of KC8 in the presence of one equivalent of cAAC. In the solid state, compound 2 is stable at room temperature for a long time under inert conditions. The reduction of compound 1 in the presence of one equivalent KC8 resulted in the first stable silicon trifluoride monoradical (cAAC)SiF3 (3).