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

Department of Chemistry, Inorganic Chemistry Section, Jadavpur University, Calcutta-700 032, India Manuscript received 9 September /999, accepted 26 February 2000 Reaction of phenols containing a second donor site linked to the ortho-positlon [viz. 2,4,6-tribromophenol (HL1) 2-nitrophcnol (HL2) and 2,4,6-trinitrophcnol (HL3)] with [Ru(bpy)2Cl2] in the presence or a base has afforded complexes of the type [Ru(bpy)2(L)]+ (where L stands for the deprotonated ligands), which have been isolated as perchlorate salts in the solid state. The complexes arc diamagnetic (low-spin d6, 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) shows a RuII-RuIII oxidation within 0.63 to 0.93 V vs SCE and one reduction of the coordinated bpy within -1.42 to -1.68 V vs SCE