Catalytic Activity of Gold(I) Complexes with Hemilabile P,N Ligands.

Two new cationic dinuclear gold(I) complexes, [Au {μ(P,N)-5} ]X -in which X=NTf (7; Tf=trifluoromethanesulfonate) or SbF (8) and 2-(diphenylphosphanyl)benzonitrile (5) is a P,N-bridging donor-have been synthesized and structurally characterized. These air-stable species and their dimeric and polymeric analogues possessing 1'-(diphenylphosphanyl)-1-cyanoferrocene (1) as the bridging ligand, Au {μ(P,N)-1} and [Au{μ(P,N)-1}] [SbF ] , were used as precatalysts in various Au-mediated C-C and C-O bond-forming reactions. The reactivity of these complexes revealed the hemilabile nature of their P,N ligands. In the series of tested precatalysts, complex 8 exerted particularly high catalytic activity at low Au loading, even in reactions that usually require high amounts of gold catalyst to proceed efficiently under standard reaction conditions.