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 [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 [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.