Electrochemical behavior of the triple-decker sandwich cobalt and nickel complexes with cyclo-triphosphorus and cyclo-triarsenic

Cyclic voltammetry was used in the title study. Preliminary work on the Co complexes, recently synthesized by a known method, indicated that reversible 3-step voltammograms (a 1-electron oxidn. and 2 one-electron redns.) can be obtained at the Pt electrode for Co2P2+ and Co2As2+ (where the complex consists of two 1,1,1-tris(diphenylphosphinomethyl)ethane ligands and a bridged triphosphorus or the corresponding As analogs) in MeCN using Et4NBF4 as supporting electrolyte. A similar study could not be carried out for Ni2P2+ and Ni2As2+ owing to their instability in MeCN. This was also found in dimethyl sulfoxide and DMF. Two reversible 1-electron steps, assocd. with the +2/+3 and +2/+1 redox changes were detected voltammetrically for the Ni complexes. The electrode potential values assocd. with the redox steps occurring in Me2CO are also reported.