Structure and Solution Reactivity of (Triethylsilylium)triethylsilane Cations

Reaction of triphenylmethylium tetrakis(pentafluorophenyl)borate, [Ph3C] [B(C6F5)(4)], with excess neat triethylsilane affords triethylsilylium(triethylsilane) tetrakis(pentafluorophenyl)borate, [(Et3Si)(2)(mu-H)] [B(C6F5)(4)] (1), identified by X-ray crystallography. In chlorobenzene and fluorobenzene, 1 is observed in solution. When 1 is dissolved in benzene or toluene, the evolved gas was shown to be hydrogen. Isotope labeling experiments demonstrate that the hydrogen arises from the reaction of Et3SiH with the silylium complex of the arene solvent.