Synthesis, characterisation, electrochemistry and reactivity of osmium-palladium carbonyl complexes containing 1,1′-bis(diphenylphosphino)ferrocene (dppf); molecular structures of [Os₅PdC(CO)₁₄(μ-dppf)], [OsPd(μ-I)₂I₂(CO)₂(H-dppf)]₂and [{Os₅C(CO)₁₄}₂(μ-dppf)]

The hexanuclear osmium-palladium carbonyl carbide cluster [Os5PdC(CO)14(μ-dppf)] 1 [dppf = 1,1′-bis(diphenylphosphino)ferrocene] has been synthesized in 56% yield by the reaction of [N(PPh3)2]2[Os5C(CO)14] with [Pd(dppf)(H2O)2][O3CCF3]2. When treated with iodine in CH2Cl2at ambient conditions, compound 1 underwent cluster degradation to give the macrocyclic complex [OsPd(μ-I)2I2(CO)2(μ-dppf)]22. Thermolysis of complex 1 in refluxing chloroform gave the dppf bridged dimeric cluster [{Os5C(CO)14}2(μ-dppf)] 3. The structures of 1-3 were characterised by IR,1H,31P NMR and mass spectroscopies and X-ray crystallography. Electrochemical investigations revealed that complex 1 underwent a reversible one-electron oxidation at the ferrocene centre followed by a quasi-reversible oxidation of the metal cluster core.