Mixed-metal clusters redox condensation

The reaction of a carbonylmetalate with a neutral metal carbonyl has been labeled a redox condensation by Chini et al. (40, 41) and has been as widely used as a pyrolysis reaction for synthesizing mixed-metal clusters. Carbonylmetalates usually react rapidly with most neutral carbonyls, even under very mild conditions. A large number of mixed-metal hydride clusters have been formed via this type of reaction, primarily because the initial products are anionic clusters that in many cases may be protonated to yield the neutral hydride derivative. 

A logical extension of the synthesis of [Co6(CO)i5]2- from [Co(EtOH) J [Co(CO)4]2 has been successfully applied to the preparation of mixed-metal clusters. Thermal decomposition of [Ni(EtOII) J[Co (CO) 4]2 prepared in situ gives the red hexanuclear dianion [Ni2Co4(CO) n]2", through the following redox condensation and redistribution processes (44) ... 

The reaction of metal carbonyl complexes with carbonyl anions is a widely used technique for synthesis of mixed-metal clusters. This reaction is also termed reductive condensation or redox condensation. The metal carbonyl anion may be generated in situ or may be separately isolated. The mixed-metal product is usually an anion protonation can be used to generate a neutral cluster hydride. 

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