Homo- and Heteroleptic Silylstannylenes: Synthesis, Structure and Use as Precursors to Bimetallic Compounds.

Two novel silyl-substituted stannylenes are reported: ArMesSn-{Si-(SiMe3)2(SitBuPh2)} (ArMes = 2,6-Mes2C6H3, Mes = 2,4,6-Me3C6H2) and Sn-{Si-(SiMe3)2(SitBuPh2)}2, the latter representing a very rare example of a homoleptic disilyl stannylene Together with the known stannylene ArMesSn-{Si-(SiMe3)3}, these systems are each shown to insert into the Au-Cl bond of (Ph3P)-AuCl to form complexes of the type (Ph3P)-Au-(SnR2Cl) containing four coordinate stannyl ligands (where R = aryl or silyl group). Similar behavior is shown toward (Cy3P)-AuI, yielding crystalline (Cy3P)-Au-{SnI-(ArMes)-(Si-(SiMe3)3)} in the case of ArMesSn-{Si-(SiMe3)3}. Subsequent iodide abstraction to yield [(Cy3P)-Au-{Sn-(ArMes)-(Si-(SiMe3)3)}]+ can be achieved using Li-[Al-(OR f )4] (R f = -C-(CF3)3), facilitated by the long tin-halide bond and strongly electron-donating tertiary phosphine ligand. This cationic complex represents the first structurally characterized example of a simple (two-coordinate) stannylene ligand bound to a gold center in a manner analogous to classical Au-(I) carbene complexes.