Reactivity of Silylene with Gallium- and Boron Trihalide at Reductive Conditions Resulting in Unforeseen Products

Herein, we report a one-pot reaction of gallium and boron halides with potassium graphite in the presence of benzamidinate stabilized silylene LSi-R, (L=PhC(N^t Bu)₂ ). The reaction of LSiCl with an equivalent amount of GaI₃ in the presence of KC₈ leads to the direct substitution of one chloride group by gallium diiodide simultaneously additional coordination of silylene resulted in L(Cl)Si→GaI₂ -Si(L)→GaI₃ (1). In compound 1, the structure comprises two differently coordinated gallium atoms where one gallium presents between two silylenes and the other gallium is only coordinated by one silylene. In this Lewis acid-base reaction the oxidation states of the starting materials remain unchanged. The same is valid in the silylene boron adduct formation of L(^t Bu)Si-BPhCl₂ (2) and L(^t Bu)Si-BBr₃ (3). This new route provides access to galliumhalosilanes challenging to synthesize by any other method.