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 Ru^II-Ru^III 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.