Electrochemistry of transition metal π-complexes. IV. Oxidation of cyclopentadienyl diolefine and cyclobutadiene cobalt complexes

Electrochemical oxidation of cobalt sandwich complexes CoCpL, where Cp is η5-cyclopentadienyl and L an η4-diolefine or cyclobutadiene ligand, was investigated by means of cyclic voltammetry and polarography. Oxidation is reversible or nearly so for compounds where L is a cyclic diolefine (I–III) or a cyclobutadiene (VI) and for the methylated complexesCo(C5Me5)(C5Me5R) (R = Me, Ph) (VII) and irreversible for CoCp(C5H5Ph) (IV) and the complexes V where L is a divinylborane.