Chemistry of some ruthenium phenolates. Synthesis, characterization and redox properties

Reaction of phenols containing a second donor site linked to the ortho-posi tion [viz. 2,4,6-tribromophenol (HL1), 2-nitrophenol (HL2) and 2,4,6-trinit rophenol (HL3)] with [Ru(bpy)(2)Cl-2] in the presence of a base has afforde d complexes of the type [Ru(bpy)(2)(L)](+) (where L stands for the deproton ated ligands), which have been isolated as perchlorate salts in the solid s tate. The complexes are diamagnetic (low-spin d(6), S = 0) and in solution show several MLCT transitions in the visible region. Cyclic voltammetry of the [Ru(bpy)(2)(L)](+) complexes in acetonitrile solution (0.1 M TEAP) show s a Ru-II-Ru-III oxidation within 0.63 to 0.93 V vs SCE and one reduction o f the coordinated bpy within -1.42 to -1.68 V vs SCE.