Electrochemical studies of nitroprusside in the presence of copper(II): formation of Cu(I) reduced nitroprusside species

Cu2+ is reduced in the presence of nitroprusside to form two Cu(I) reduced nitroprusside species at about +0.050 V (pH 7.6). These species are reduced further at about −0.60 V. The two species are formed by an EC mechanism, and the species are believed to be [CuIFe(CN)4NO]−, which predominates in acidic solution, and [CuIFe(CN)5NO]2−, which predominates in alkaline solution. These conclusions are supported by cyclic voltammetric and bulk electrolysis/coulometric experiments.