Synthesis, structures, and catalytic oxidation of three aqua-coordinated and oxo-bridged diruthenium(III) complexes with sulfobenzoate and 2,2′-bipyridine

Abstract

Three new diruthenium(III) complexes, [Ru2O(2-sb)2(2,2′-bipy)2(H2O)2]·2.5H2O (1), [Ru2O(3-sb)2(2,2′-bipy)2(H2O)2]·9H2O (2), and [Ru2O (4-sb)2(2,2′-bipy)2(H2O)2]·9H2O (3), where sb2− is sulfobenzoate dianion and 2,2′-bipy is 2,2′-bipyridine, were synthesized using hydrothermal methods and characterized by IR, elemental analysis, thermogravimetric analysis, UV–vis, and fluorescence spectra. The single crystal X-ray analysis showed that each of these complexes has a dinuclear core stabilized by two bridging carboxylates and one bridging O2−. Variable sb2− ligands (2-sb, 3-sb, and 4-sb) in these complexes lead to diverse electronic spectroscopic behavior. The efficiency of activating methyl phenyl sulfide oxidation utilizing H2O2 in 3 equiv. was studied at 23 ± 2 °C. The effect of the amount of catalyst and solvents on activities was investigated. Under optimized reaction conditions, the major product was sulfoxide. Complex 1 gave significant conversion of 100 and 98% selectivity for sulfoxide after 4 h.