Kinetic, mechanistic and spectral investigations of ruthenium(III)-catalysed oxidation of 4-hydroxycoumarin by alkaline diperiodatonickelate(IV) (stopped flow technique)

Oxidation of a Anticholinergic Drug Atropine Sulfate Monohydrate by Alkaline Copper(III) Periodate Complex: A Kinetic and Mechanistic Study

The oxidation of a anticholinergic drug, Atropine sulfate monohydrate (ASM) by diperiodatocuprate(III) (DPC) has been investigated spectrophotometrically in aqueous alkaline medium at a constant ionic strength of 0.50 mol dm-3. The reaction between diperiodatocuprate(III) and atropine sulfate exhibits1:2stoichiometry (atropine sulfate: diperiodatocuprate(III)). The main oxidation products were identified and confirmed by spectral studies including IR,1H NMR and GC-MS. A suitable mechanism is proposed. The order with respect to diperiodatocuprate(III) concentration was unity, while the order with respect to atropine sulfate concentration was less than unity over the concentration range studied. The rates increased with an increase in alkali concentration and decreased with an increase in periodate concentration. The activation parameters with respect to slow step of the mechanism were calculated and the thermodynamic quantities we are also determined. Kinetic experiments suggest that [Cu(OH)2(H3IO6)]-is the reactive species of copper(III).

Kinetic and Mechanistic Aspects of Osmium(VIII) Catalyzed Oxidation of DL-ornithine by Copper(III) Periodate Complex in Aqueous Alkaline Medium

The oxidation of DL-ornithine monohydrochloride (OMH) by diperiodatocuprate(III) (DPC) has been investigated in the presence of osmium(VIII) catalyst in aqueous alkaline medium at a constant ionic strength of 0.20 mol dm−3spectrophotometrically. The reaction exhibits 1:4 stoichiometry i.e., [OMH]: [DPC]. The order of the reaction with respect to [DPC] was unity while the order with respect to [OMH] was less than unity over the concentration range studied. The rate increased with an increase in [OH–] and decreased with an increase in [IO4−]. The order with respect to [Os(VIII)] was unity. The reaction rates revealed that Os(VIII) catalyzed reaction was about nine-fold faster than the uncatalyzed reaction. The oxidation products were identified by spectral analysis. Suitable mechanism has been proposed. The reaction constants involved in the different steps of the reaction mechanism were calculated. The catalytic constant (KC) was also calculated at different temperatures. The activation parameters with respect to slow step of the mechanism and also the thermodynamic quantities were determined. Kinetic experiments suggest that [OsO4(OH)2]2−is the reactive Os(VIII) species and [Cu(H2IO6)(H2O)2] is the reactive copper(III) species.