4 research outputs found
Nitrite reduction mediated by the complex RuIII(EDTA)
Reported is the first example of a ruthenium(III)-complex, RuIII(EDTA) (EDTA4β = ethylenediaminetetraacetate), that mediates O-atom transfer from nitrite to the biological thiols cysteine and glutathione, leading to the formation of [RuIII(EDTA)(NO+)]0. However, at pH below 5.0, the coordinated nitrite ion in the [RuIII(EDTA)(NO2)]2β complex undergoes proton-assisted decomposition, resulting in the formation of a [RuIII(EDTA)(NO+)]0 species
Mechanism of the oxidation of thiosulfate with hydrogen peroxide catalyzed by aqua-ethylenediaminetetraacetatoruthenium(III)
Catalytic ability of [RuIII(edta)(H2O)]β (edta4β = ethylenediaminetetraacetate) complex toward oxidation of thiosulfate (S2O32β) in presence of H2O2 has been explored in the present work. The kinetics of the catalytic oxidation of thiosulfate (S2O32β) has been studied spectrophotometrically as a function of [RuIII(edta)], [H2O2], [S2O32β] and pH. Spectral analyses and kinetic data indicate a catalytic pathway involving activation of both substrate (S2O32β) and oxidant (H2O2). Substrate activation pathway involves the formation of a red [RuIII(edta)(S2O3)]3β species through the reaction of the [RuIII(edta)(H2O)]β catalyst complex and the substrate (S2O32β). Hydrogen peroxide reacts directly with thiosulfate coordinated to the RuIII(edta) complex to yield sulfite as immediate oxidation product. Peroxide activation pathway is governed by the formation of [RuV(edta)(O)]β catalytic intermediate which oxidize thiosulfate, however, at slower rate (View the MathML source at 25 Β°C) as compared to the rate of oxidation of the coordinated thiosulfate (View the MathML source at 25 Β°C). Sulfite and sulfate were found to be the oxidation products of the above described catalytic oxidation process. A detailed mechanism in agreement with the spectral and kinetic data is presented