Electrochemical behaviour of five-co-ordinate nitrosyl cobalt complexes in an aprotic medium

The cathodic and anodic behaviour of some five-co-ordinated nitrosyl cobalt complexes of the type [CoXL3(NO)][BPh4][X = Cl or I, L = P(OEt)3 or P(OMe)3] has been investigated at platinum electrodes in acetonitrile solvent. Four-co-ordinated mononitrosyl cobalt compounds of formula [CoL3,(NO)] are formed via an e.c.e. type reduction mechanism (electron transfer followed by a chemical reaction followed by electron transfer). The anodic oxidation of these [CoL3(NO)] compounds has also been studied. The [CoXL3(NO)][BPh4] complexes with L = P(OEt)3 undergo a complicated oxidation process leading to the dinitrosyl [CoL2(NO)2][BPh4] and [CoXL(NO)2] compounds and to species containing no nitrosyl ligand. The chemical reactions associated with the charge-transfer steps involve traces of water.