title: Remarkably high catalytic activity of the Ru(III)(edta)/H2O2 system towards degradation of the azo-dye Orange II.
abstract: The Ru(III)(edta)/H(2)O(2) system (edta(4-) = ethylenediaminetretaacetate) was found to degrade the azo-dye Orange II at remarkably high efficiency under ambient conditions. Catalytic degradation of the dye was studied by using rapid-scan spectrophotometry as a function of [H(2)O(2)], [Orange II] and pH. Spectral analyses and kinetic data point towards a catalytic pathway involving the rapid formation of [Ru(III)(edta)(OOH)](2-) followed by the immediate subsequent degradation of Orange II prior to the conversion of [Ru(III)(edta)(OOH)](2-) to [Ru(IV)(edta)(OH)](-) and [Ru(V)(edta)(O)](-)via homolysis and heterolysis of the O-O bond, respectively. The higher oxidation state Ru(IV) and Ru(V) complexes react three orders of magnitude slower with Orange II than the Ru(III)-hydroperoxo complex. In comparison to biological oxygen transfer reactions, the Ru(edta) complexes show the reactivity order Compound 0 ≫ Compounds I and II.
authors.affiliation: Chemistry and Biomimetics Group, Central Mechanical Engineering Research Institute, Durgapur, 713209, India.
authors.forename: Debabrata
authors.initials: D
authors.lastname: Chatterjee
authors.forename: Erika
authors.initials: E
authors.lastname: Ember
authors.forename: Ujjwal
authors.initials: U
authors.lastname: Pal
authors.forename: Sarita
authors.initials: S
authors.lastname: Ghosh
authors.forename: Rudi
authors.initials: R
authors.lastname: van Eldik
mesh_terms: D001391:Azo Compounds / Q000737:chemistry*; D001557:Benzenesulfonates / Q000737:chemistry*; D002384:Catalysis; D004396:Coloring Agents / Q000737:chemistry*; D056831:Coordination Complexes / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry*; D007700:Kinetics; D010084:Oxidation-Reduction; D012428:Ruthenium / Q000737:chemistry*
chemical_list: D001391:Azo Compounds; D001557:Benzenesulfonates; D004396:Coloring Agents; D056831:Coordination Complexes; D012428:Ruthenium; D006861:Hydrogen Peroxide; C014722:2-naphthol orange