Impact of a rigid backbone on the structure of an agostically-stabilised dialkylstannylene: isolation of an unusual bridged stannyl-stannylene†

The reaction between the phosphine–borane-stabilised dicarbanion complex [1,2-C6H4{CHP(BH3)Cy2}2][Li(THF)n]2 and Cp2Sn gives the unusual stannyl–stannylene [[1,2-C6H4{CHP(BH3)Cy2}2]Sn]2·1½PhMe, in which one dicarbanion ligand chelates a tin centre, while the other bridges a tin–tin bond. The stannylene centre is stabilised by an agostic-type B–H⋯Sn interaction.