摘要:
A range of trinuclear metallocene and metallocenium complexes have been prepared using the ferrocene-functionalized lithium salts Li+(FcCMe(2)C(5)H(4))- (2; Fc = Fe(eta-C5H5)(eta-C5H4)), Li+{FcC(=CH2)C5H4}(-) (4), and Li+(Fc''CH2C5H4)(-) (8; Fc'' = Fe(eta-C(5)Me(4)H)(eta-C(5)Me(4))). The triferrocenes (FcCMe(2)C(5)H(4))(2)Fe (3) and (FcC(=CH2)C5H4)(2)Fe (5) consist of a central ferrocene. linked by single-cal;bon bridges to two terminal ferrocene units, whereas (Fc''CH2C5H4)(2)M (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''CH2C5H4)(2)Fe}(2+)(TCNE(-))(2) (17; TCNE = tetracyanoethylene) and {(Fc''CH2C5H4)(2)Co}(3+)(TCNE(-))(3)(18) have been prepared and their magnetic properties investigated.