Kinetics and mechanism of the [Ru(III)(edta)(H2O)](-)-mediated oxidation of cysteine by H2O2.

The kinetics and mechanism of the [Ru(III)(edta)(H(2)O)](-)-mediated oxidation of cysteine (RSH) by hydrogen peroxide (edta(4-) = ethylenediaminetetraacetate), were studied in detail as a function of both the hydrogen peroxide and cysteine concentrations at pH 5.1 and room temperature. The kinetic traces reveal clear evidence for a catalytic process in which hydrogen peroxide reacts directly with cysteine coordinated to the Ru(III)(edta) complex in the form of [Ru(III)(edta)SR](2-).

Remarkably high catalytic activity of the Ru(III)(edta)/H2O2 system towards degradation of the azo-dye Orange II.

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.

Redox reactions of a Ru(III)-edta complex with thioamino acids. Kinetic and mechanistic studies.

The kinetics of reduction of [Ru(III)(edta)pz]⁻ (edta⁴⁻ = ethylenediaminetetraacetate; pz = pyrazine) by thioamino acids (RSH = cysteine, glutathione) resulting in the formation of a red [Ru(II)(edta)pz]²⁻ species (λ(max) = 462 nm) has been studied spectrophotometrically using both conventional mixing and stopped-flow techniques. The time course of the reaction was followed as a function of [RSH], pH, temperature and pressure. Alkali metal ions were found to have a positive influence (K(+) > Na(+) > Li(+)) on the reaction rate.

Kinetics and mechanism of NO production in the Ru(III)-(edta) mediated oxidation of L-arginine with H(2)O(2).

The kinetics of the Ru(III)-(edta) (edta(4-) = ethylenediaminetetraacetate) catalyzed oxidation of l-arginine by H(2)O(2) mimicking the action of nitric oxide synthases (NOSs) has been studied spectrophotometrically. The time course of the reaction of [Ru(V)(edta)O](-) with l-arginine was followed at 390 nm under catalytic turn-over conditions. Formation of NO in the reacting system has been confirmed with an isolated nitric oxide free radical analyzer.

Convenient route to both enantiomers of a highly functionalized trans-disubstituted cyclopentene. Synthesis of the carbocyclic core of the nucleoside BCA.

[structures: see text] Synthesis of both enantiomers of a highly functionalized cyclopentenol derivative, versatile building block for a vast array of biologically active compounds, is described. The key steps involve stereocontrolled synthesis of a diene with two syn-disposed substituents from a (R)-(+)-glyceraldehyde derivative, ring-closing metathesis of this diene, and functional group manipulation of the resulting trans-disubstituted cyclopentene. One of the enantiomers of the cyclopentenol thus obtained has been converted to an amino cyclopentene, the carbocyclic core of the nucleoside (-)-BCA, a potent inhibitor of HIV reverse transcriptase.