Electrocarboxylation of chloroacetonitrile mediated by a Ni(I) terpyridine complex: Voltammetric and spectroscopic studies

Cyclic voltammetry and spectroelectrochemistry (e.p.r.) were used to investigate the mechanisms implied in electrocarboxylation of chloroacetonitrile (Cl-CH2-CN, noted RCl) mediated by [Ni(II)(terpy)2]2+. The oxidative addition on electrogenerated [Ni(I)(terpy)]+ yields an alkyl-nickel R-Ni(III) complex which is reduced into alkyl-nickel(II). E.p.r study shows that homolytic nickel-carbon bond cleavage seems be more probable pathway form organic radical R-which R−. Under carbon dioxide atmosphere, cyclic studies show CO2 was added alkyl-Ni(III) giving probably a adduct RCO2-Ni(II) allowing release carboxylate RCO2− active complex. Controlled potential electrolyses showed good carboxylated faradic obtained.