Synthesis of a Heptanuclear Rhenium−Iridium Carbido Carbonyl Cluster and of (Triphenylphosphine)gold(I) Derivatives

The octanuclear cluster [Re5Ir(μ6-C)(CO)17(μ3-Re(CO)3)2]2- loses a [Re(CO)3]+ capping unit in refluxing acetonitrile to give the heptanuclear cluster [Re5Ir(μ6-C)(CO)17(μ3-Re(CO)3)]3-. The latter compound can be capped with [AuPPh3]+ groups to form the monogold and digold derivatives [Re6IrC(CO)20(AuPPh3)]2- and [Re6IrC(CO)20(AuPPh3)2]-. These three new anionic clusters have been isolated as PPN+ and/or PPh4+ salts and are formulated on the basis of microanalytical and FAB mass spectrometric data. The solid-state structure of [PPh4][Re6Ir(μ6-C)(CO)20(μ3-AuPPh3)2]·CH2Cl2 has been determined by X-ray diffraction. Crystal data: triclinic, space group P1̄, a = 13.1182(1) Å, b = 15.1806(1) Å, c = 23.4061(3) Å, α = 74.251(1)°, β = 82.058(1)°, γ = 70.306(1)°, Z = 2. Further information on the structures of the compounds in solution has been derived from 13C and 31P NMR studies.