Synthesis and electrocatalytic properties of a cis-diaquo-ruthenium(II) complex with 6,6'-dichloro-2,2'-bipyridine

Abstract

The syntheses of cis-[RuII(6,6'-Cl2bpy)2(OH2) 2(ClO4)2, cis-[RuVI(6,6'-Cl2bpy)2]O)2] ClO4)2 and cis-[RuII(6,6'-Cl2bpy) 2(CH3CN)2](ClO4)2 ·H2O complexes are described. In 0.1 M CF3COOH, cis-[RuII (6,6'-Cl2bpy)2(OH2)2]2+ exhibits two quasi-reversible, two-electron couples at 0.93 and 1.17 V vs. SCE assignable to the cis-[RuVI(6,6'-Cl2bpy)2(O)(OH2 )]2+/cis-[RuII(6,6'-Cl 2bpy)2(OH2)2]2+ and the cis-[RuVI(6,6'-Cl2bpy)2(O)2] 2+/cis- [RuVI(6,6'-Cl2bpy)2(O)(OH2)] 2+ couples, respectively. The formal potentials of both couples shift to more negative values by 60 mV per unit pH change as the pH of the medium is raised. cis-[RuVI (6,6'-Cl2bpy)2(O)2)]2+ generated electrochemically is an active catalyst for the oxidation of alcohols, tetrahydrofuran, dextrose and chloride. Incorporation of cis-[RuII(6,6'-Cl2bpy) 2(OH2)2]2+ into Nafion® films on the electrodes produces electrodes at which the rate of oxidation of organic substrates and chloride ion is enhanced. © 1992.