New synthesis of a stable dialkylstannylene and its reversible complexation with tetrahydrofuran

A stable dialkylstannylene [2,2,5,5-tetrakis(trimethylsilyl)stannacyclopentane-1,1-diyl] was synthesized by the reduction of the corresponding dichlorostannane with KC8 in THF at low temperature. The stannylene showed reversible complexation with tetrahydrofuran (THF) with ΔH=−7.0 kcal mol−1 and ΔS=−48 cal mol−1 K−1, suggesting that the complexation is energetically favored but disfavored by the steric hindrance. No such complexation with THF was observed for the corresponding germylene and silylene.