Cobaltocene and cobaltocenium complexes

Cobaltocene compounds have been amply discussed in COMC (1982) and COMC (1995) which should be consulted for reviews. Some specific properties of cobaltocenium derivatives will be discussed in this section. 

The Bu 4-t-indacene ligand afforded a mixture of as- and /raor-isomers of a di(cobalt-Cp) adduct. These neutral compounds 356 and 357 interconverted in solution. The oxidation of these compounds by NH4BF4 afforded the corresponding dicobalticinium derivatives 358 and 359, in which the t-indacene ligand has been protonated at the 4,8-positions. These new complexes did no more interconversion (Equation (60)). 

Prior to this work, Manriquez et al. published the synthesis of polydecker complexes 360 and 361a that could somehow mimic one-dimensional (ID) otganometallic polymers (Equation (61)).  

Unfortunately, as a quadruple decker was obtained (which contained however only iron), no further results in this potentially very interesting area were published until then. A somewhat related dinuclear compound has been obtained while attempting the synthesis of l-formyl-l, 2, 3, 4, 5 -pentamethylcobaltocene. This compound was only made in situ as it rearranged into dimeric species 362 by redox disproportionation with radical coupling (Equation (62)).  

The donor-acceptor heterodimetallic fV,Ch-compound 361b displayed interesting NLO properties 

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