Synthesis, characterisation, electrochemistry and reactivity ofosmium-palladium carbonyl complexes containing1,1′-bis(diphenylphosphino)ferrocene (dppf); molecular structuresof [Os5PdC(CO)14(µ-dppf)],[OsPd(µ-I)2I2(CO)2(µ-dppf)]2 and[{Os5C(CO)14}2(µ-dppf)]

Abstract

The hexanuclear osmium–palladium carbonyl carbide cluster [Os 5 PdC(CO) 14 (µ-dppf)] 1 [dppf = 1,1′-bis(diphenylphosphino)ferrocene] has been synthesized in 56% yield by the reaction of [N(PPh 3 ) 2 ] 2 [Os 5 C(CO) 14 ] with [Pd(dppf)(H 2 O) 2 ][O 3 CCF 3 ] 2 . When treated with iodine in CH 2 Cl 2 at ambient conditions, compound 1 underwent cluster degradation to give the macrocyclic complex [OsPd(µ-I) 2 I 2 (CO) 2 ( µ-dppf)] 2 2. Thermolysis of complex 1 in refluxing chloroform gave the dppf bridged dimeric cluster [{Os 5 C(CO) 14 } 2 (µ- dppf)] 3. The structures of 1–3 were characterised by IR, 1 H, 31 P 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.