Redox behaviour of mixed-ligand five-coordinate cobalt(I) complexes with isocyanides and phosphines

The oxidation mechanism of a series of mixed-ligand five-coordinate cobalt(I) complexes of the type [Co(CNR) 3 L 2 ] + (R = C 6 H 5 , 4-CH 3 C 6 H 4 , 4-CH 3 OC 6 H 4 , 4-NO 2 C 6 H 4 , and 2,6-(CH 3 ) 2 C 6 H 3 ; L = P(OCH 3 ) 3 and P(C 6 H 5 )(OC 2 H 5 ) 2 ) on mercury and platinum electrodes in dichloromethane is described. The primary reversible electron transfer between electrode and depolarizer is followed by a fast chemical reaction which brings about a change in configuration (and a dimerization). Correlations between redox properties of the species and their structural features are discussed.