Nickel-iridium carbonyl clusters. Synthesis and solid-state structure of the trianion [Ir3Ni6(μ-CO)6(μ3-CO) 2(CO)9]3-. The first example of a mixed iridium-nickel carbonyl cluster

The dark brown [Ir3Ni6(μ-CO)6(μ3-CO) 2(CO)9]3- trianion has been obtained by redox condensation between [Ni(CO)4] and [Ir(CO)4]-. This new mixed-metal cluster is rapidly degraded, at room temperature and atmospheric pressure, by carbon monoxide to form the [Ni(CO)4] and [Ir(CO)4]- parent mononuclear compounds. The salt [NMe2(CH2Ph)2]3[Ir 3Ni6(CO)17] crystallizes in the monoclinic space group P21/c (no. 14) with a = 24.295(4), b = 12.765(3), c = 23.898(5), β = 113.68(1)°, and Z = 4. The structure was solved by conventional Patterson and Fourier methods and refined by full-matrix least squares to a final R value of 0.032 for 6 169 independent reflections having I > 3σ(I). The metal framework consists of a face-sharing bioctahedron, with the three iridium atoms located in the inner triangle.