The water-soluble cluster cation [H3Ru3(C6H6)(C6Me6)(2)(O)](+): Improved synthesis, aerobic oxidation, electrochemical properties and ligand exchange studies

The synthesis of the trinuclear cluster cation H3RU3(C6H6)(C6Me6)(2)(O) (1) has been considerably improved by changes in the NaBH4 addition step and by introducing chromatographic methods; in addition, the redox and ligand exchange properties of 1 have been studied. Although exposure of ail aqueous solution of 1 to air yields the oxidised cluster H2RU3(C6H6)(C6Me6)(2)(O)(OH) (2), cyclic voltammetry of [1][BF4] in acetonitrile reveals a first reversible oxidation step that does not involve 2. Bulk electrolysis of I and 2 in the same medium affords only decomposition products. Ligand exchange in I takes place only at higher temperatures: by heating a mixture of toluene with ail aqueous solution of [1][BF4] (1000: 1) to 110 degrees C for 2 h, the formation of the toluene derivative H3RU3(C6H5Me)(C6Me6)(2)(O) (3) is observed in small quantities. H/D exchange of 1 with D2O does not occur up to 90 degrees C however, in the presence of D-2, H/D exchange with 1 is observed to give the deuterated derivative D3RU3(C6H6)(C6Me6)(2)(O) (1a). The results provide ail improved synthesis of 1, as well as information about its redox and ligand-exchange reactions, results necessary to understand and develop the chemistry of 1.