title: Oxidation of thiocyanate with H2O2 catalyzed by [Ru(III)(edta)(H2O)]-.
abstract: The [Ru(III)(edta)(H2O)](-) (edta(4-) = ethylenediaminetetraacetate) complex is shown to catalyze the oxidation of thiocyanate (SCN(-)) with H2O2 mimicking the action of peroxidases. The kinetics of the catalytic oxidation process was studied by using stopped-flow and rapid scan spectrophotometry as a function of [Ru(III)(edta)], [H2O2], [SCN(-)], pH (3.2-9.1) and temperature (15-30 °C). Spectral analyses and kinetic data are suggestive of a catalytic pathway in which hydrogen peroxide reacts directly with thiocyanate coordinated to the Ru(III)(edta) complex. Catalytic intermediates such as [Ru(III)(edta)(OOH)](2-) and [Ru(V)(edta)(O)](-) were found to be non-reactive in the oxidation process under the specified conditions. Formation of SO4(2-) and OCN(-) was identified as oxidation products in ESI-MS experiments. A detailed mechanism in agreement with the spectral and kinetic data is presented.
authors.affiliation: Chemistry and Biomimetics Group, CSIR-Central Mechanical Engineering Research Institute, MG Avenue, Durgapur, 713209, India. dchat57@hotmail.com
authors.forename: Debabrata
authors.initials: D
authors.lastname: Chatterjee
authors.forename: Barnali
authors.initials: B
authors.lastname: Paul
authors.forename: Rupa
authors.initials: R
authors.lastname: Mukherjee
mesh_terms: D002384:Catalysis; D003485:Cyanates / Q000138:chemical synthesis / Q000737:chemistry; D004492:Edetic Acid / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010084:Oxidation-Reduction; D012428:Ruthenium / Q000737:chemistry*; D013431:Sulfates / Q000138:chemical synthesis / Q000737:chemistry; D013696:Temperature; D013861:Thiocyanates / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D003485:Cyanates; D009942:Organometallic Compounds; D013431:Sulfates; D013861:Thiocyanates; D014867:Water; D012428:Ruthenium; D004492:Edetic Acid; D006861:Hydrogen Peroxide; C031760:thiocyanate