Reaction of ethynediyl, butadiynediyl and ethynyl iron complexes, (η5-C5R5)(CO)2Fe–(C
详细信息 查看全文
文摘
Polynuclear C2 and C4 cluster compounds are prepared by treatment of the iron complexes containing μ-C2 (ethynediyl), μ-C4 (butadiynediyl) and C2H (ethynyl) ligands with Fe2(CO)9. The ethynediyl complex (η5-C5Me5)(CO)2Fe–CC–Fe(η5-C5Me5)(CO)2 gives the tetrairon dicarbide complex, (μ4-C2)Fe4(η5-C5Me5)2(CO)9, which shows dynamic behavior by way of reversible scission and recombination of the Fe–Fe bonds. Reaction of the butadiynediyl complex, (η5-C5 Me5)(CO)2Fe–CC–CC–Fe(η5-C5Me5)(CO)2, affords tetranuclear nona- and decacarbonyl cluster compounds depending on the reaction conditions. The nonacarbonyl cluster compound formed exclusively in benzene adopts a normal acetylide cluster type structure and one of the two CC functional groups remains unreacted, but the decacarbonyl cluster isolated as a minor product from the reaction in THF consists of a μ3-η3-propargylidene diiron core and a ketene functional group, which should be formed by addition of an Fe2 unit followed by migration of CO to the terminal carbon atom of the C4 bridge. In contrast, reactions of polyynyl complexes are found to be less selective. Reaction of (η5-C5Me5)(CO)2Fe–CC–H results in the formation of a low yield mixture of products, of which the p-quinone complex, c-2,5-[Fe(η5-C5Me5)(CO)2]2–C6H2O2, has been isolated and characterized by X-ray crystallography, though (η5-C5Me5)(CO)2Fe–CC–CC–H merely gives an intractable reaction mixture.