| Sumario: | A range of trinuclear metallocene and metallocenium complexes have been prepared using the ferrocene-functionalized lithium salts Li+(FcCMe2C5H4)- (2; Fc = Fe(η-C5H5)(η-C5H4)), Li+{FcCi=CH2)C5H4}- (4), and Li+(Fc″CH2C5H4)- (8; Fc″ - Fe(η-C5Me4H)(η-C5Me4)). The triferrocenes (FcCMe2C5H4)2Fe (3) and {FcC(=CH2)C5H4}2Fe (5) consist of a central ferrocene linked by single-carbon bridges to two terminal ferrocene units, whereas (Fc″CH2C5H4)2M (M = Fe (9), Co (10), Cr (11)) have terminal octamethylferrocene units. Cyclic voltammetry experiments reveal that 3 and 5 exhibit three reversible redox processes, indicating significant electrostatic interactions between the metal centers in these complexes. For 9 and 10 two redox events are observed. A range of metallocenium salts with diamagnetic and paramagnetic anions has also been synthesized from these trimetallocenes. Variable-temperature magnetic susceptibility data on paramagnetic trimetallocenes and trimetallocenium salts all obey the Curie-Weiss law, with no evidence for significant spin-spin exchange interactions between metal centers. The charge-transfer salts {(Fc″CH2-C5H4)2Fe} 2+(TCNE-)2 (17; TCNE = tetracyanoethylene) and {(Fc″CH2C5H4)2Co} 3+(TCNE-)3 (18) have been prepared and their magnetic properties investigated. © 1995 American Chemical Society.
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