Electro-oxidative and electro-reductive dissociation of adducts between (η5-cyclopentadienyl) (1,2-disubstituted 1,2-ethylenedithiolato) cobalt (III) complexes and tributylphosphane or tributyl phosphite

Abstract The voltammetric characteristics of the title adducts [Co(Cp) (S 2 C 2 X 2 L] (X CN, CF 3 , COOCH 3 , 4-pyridyl, phenyl; L = tributylphosphane or tributyl phosphite) in acetonitrile solutions are reported. Both the phosphane and the phosphite adducts were oxidized and reduced through one-electron transfer processes followed by homogeneous chemical reactions for all X except phenyl; the oxidized adduct dissociated into the free complexes [Co III (Cp) (S 2 C 2 X 2 ] and the cation radical L +· , and the reduced adduct rapidly dissociated into the reduced form of the free complexes [Co II (Cp) (S 2 C 2 X 2 )] − and L. When X = phenyl, the oxidation was similar but the reduction was preceded by the dissociation of L. The oxidation and reduction half-wave potentials of the adducts were more negative than those of the corresponding free complexes, and they were linearly dependent on the adduct formation constant.