Carbonyl clusters oxidative degradation

Several other polynuclear metal carbonyls were tested as catalysts for the reduction of nitrobenzene to aniline using carbon monoxide and water as the reducing agent. Rhodium, iridium and osmium clusters were found to be very effective and they were far less susceptible to oxidative degradation than [Fe(CO)5]. 3... 

The early chemistry of hexanuclear carbonyl clusters, including those of ruthenium and osmium, has been reviewed.The hexaruthenium dianion [RuslCOlis] is prepared inside NaX-zeolite cages in 80-90% yields by treatment of [Ru(NH3)6] /NaX with CO and H2. Oxidation of the supported dianion results in cluster degradation to mononuclear ruthenium products, a process that is reversible on re-exposure to CO/H2. A redetermination of the crystal structure of Os6(CO)i8, as its chloroform solvate, confirms the bicapped tetrahedral metal core seen with the unsolvated cluster. 

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