Characterization and catalytic activity of polymer supported ruthenium schiff base complexes towards catechol oxidation

Abstract

Ruthenium(III) complexes of the Schiff bases formed by the condensation of polymer bound aldehyde and the amines, such as 1,2-phenylenediamine (PS-opd), 2-aminophenol (PS-ap), and 2-aminobenzimidazole (PS-ab) have been prepared. The magnetic moment, EPR and electronic spectra suggest an octahedral structure for the complexes. The complexes of PS-opd, PS-ap, and PS-ab have been assigned the formula [PS-opdRuCl3(H2O)], [PS-apRuCl2(H 2O)2], [PS-ab-RuCl3(H2O) 2], respectively. These complexes catalyze oxidation of catechol using H2O2 selectively to o-benzoquinone. The catalytic activity of the complexes is in the order [PS-ab-RuCl3(H 2O)2] > [PS-opdRuCl3(H2O)] ≫ [PS-apRuCl2(H2O)2]. Mechanism of the catalytic oxidation of catechol by ruthenium(III) complex is suggested to take place through the formation of a ruthenium(II) complex and its subsequent oxidation by H2O2 to the ruthemum(III) complex. © 2007 Wiley Periodicals, Inc.