1: Redox chemistry of bimetallic fulvalene complexes; 2: Oligocyclopentadienyl complexes

摘要

The electrochemistry of the heterobimetallic complexes (fulvalene)WFe(CO)(sub 5) (30) and (fulvalene)WRu(CO)(sub 5) (31) has been investigated. Compound 30 is reduced in two one-electron processes, and this behavior was exploited synthetically to prepare a tetranuclear dimer by selective metal reduction. Complex 31 displayed a distinction between the metals upon reoxidation of the dianion, allowing the formation of a dimer by selective metal anion oxidation. The redox behavior of 30 led to an investigation of the use of electrocatalysis to effect metal-specific ligand substitution. It was found that reduction of 30 with a catalytic amount of CpFe(C(sub 6)Me(sub 6)) (97) in the presence of excess P(OMe)(sub 3) or PMe(sub 3) led to the formation of the zwitterions (fulvalene)(W(CO)(sub 3)(sup (minus)))(Fe(CO)PR(sub 3)(sup +)) (107, R = P(OMe)(sub 3); 108, R = PMe(sub 3)). Compound 31 also displayed unique behavior with different reducing agents, as the monosubstituted zwitterion (fulvalene)(W(CO)(sub 3)(sup (minus)))(Ru(CO)(sub 2)(PMe(sub 3))(sup +)) was obtained when 97 was used while the disubstituted complex (fulvalene) (W(CO)(sub 3)(sup (minus))) (Ru(CO)(PMe(sub 3))(sub 2)(sup +)) was produced when Cp*Fe(C(sub 6)Me(sub 6)) was the catalyst. Potential synthetic routes to quatercyclopentadienyl complexes were also explored. Various attempts to couple heterobimetallic fulvalene compounds proved to be unsuccessful. 138 refs.