Persistent Dialkyl(silyl)stannylium Ions

The synthesis of dialkyl(silyl)stannylium borates 2[B(C6F5)4] by reaction of a stable β-silyl-substituted stannylene 3 with silylarenium borates 4[B(C6F5)4] is reported. The stannylium borates 2[B(C6F5)4] are characterized by NMR spectroscopy and single-crystal X-ray diffraction, supported by the results of quantum mechanical calculations. The accumulated experimental and theoretical data indicate that the stannylium ions 2 are not stabilized by β-silyl hyperconjugation and that intramolecular C–H/Sn+ interactions are not important.