Systemes oxydo-reducteurs du cuivre dans le dimethylsulfoxyde

Abstract

It may be concluded from the study of copper redox systems in dimethylsulfoxide that the stability of dissolved copper(I) in this solvent is greatly increased by preferential solvation of cuprous cations compared to that of cupric cations. The stability range of copper(I) is again increased in the presence of complexing reagents such as chloride, bromide and thiocyanate. Formulae and stability constants of different complexes have been determined by potentiometric titration of halide solutions of cuprous and cupric cations:. Copper(I) forms anionic complexes of type MX2- as does silver(I), the molecular compounds are however soluble; formation of cationic MX2+ or polynuclear M2X3- and M3X4- complexes could not be established, a further difference in the behaviour of copper(I) and silver(I) in dimethylsulfoxide. Copper(II) forms CuX+ and CuX2 complexes with halides which are more stable than the corresponding ones in aqueous solution although anions are still present in minor concentration. © 1972 Elsevier Sequoia S.A., Lausanne.