An intermolecular Lewis pair based on tin acid and phosphonium ylide base functions

Abstract The tin-containing Lewis acid group (C 2 F 5 ) 3 Sn was combined with a phosphonium ylide as base function in one molecule: o -[(C 2 F 5 ) 3 Sn]-C 6 H 4 (Ph) 2 PCMe 2 . It was prepared by reacting the ortho -lithiated triphenylphosphoniumdimethylmethylide ( o -Li-C 6 H 4 )(Ph) 2 PCMe 2 with the stannyl chloride (C 2 F 5 ) 3 SnCl to afford o -[(C 2 F 5 ) 3 Sn]-C 6 H 4 (Ph) 2 PCMe 2 in 86 % yield. It forms a ring structure with a bond between tin and the ylidic carbon atom both in solution and in the solid state and can thus be considered as a hidden frustrated Lewis pair. The title compound is unreactive towards H 2 , CO 2 , CS 2 , PhNCO and decomposes in the presence of SO 2 or NH 3 . However, it is active in the catalytic reduction of CO 2 with pinacolborane, H–BPin. The title compound reacts slowly with H–BPin in an unselective reaction from which a reduction product with cleaved C 2 F 5 group, the phosphonium stannate (II) o -[(C 2 F 5 ) 2 Sn]-C 6 H 4 (Ph) 2 PCHMe 2 , could be obtained in small amounts.