Osmium(VIII)/Ruthenium(III) Catalysed Oxidation of l-lysine by Diperiodatocuprate(III) in Aqueous Alkaline Medium: A Comparative Mechanistic Approach by Stopped Flow Technique |
| |
Authors: | Deepak C Hiremath Kiran T Sirsalmath Sharanappa T Nandibewoor |
| |
Affiliation: | (1) P.G. Department of Studies in Chemistry, Karnatak University, Dharwad, 580003, India |
| |
Abstract: | Abstract The kinetics of osmium(VIII) and ruthenium(III) catalysed oxidation of l-lysine (l-lys) by diperiodatocuprate(III) (DPC) in alkaline medium at a constant ionic strength of 0.15 mol dm−3 was studied spectrophotometrically. The reaction between l-lys and DPC in alkaline medium exhibits 1:2 stoichiometry in both catalysed reaction (l-lys: DPC). The reaction is first order in DPC] and has less than unit order both in l-lys] and alkali]. Increase in periodate concentration decreases the rate. Intervention of free radicals was observed in
the reaction. The main products were identified by spot test, IR and GC-MS studies. Probable mechanisms are proposed and discussed.
The reaction constants involved in the different steps of the mechanism are calculated. The activation parameters with respect
to the slow step of the mechanism are computed and discussed and thermodynamic quantities are also determined. It has been
observed that the catalytic efficiency for the present reaction is in the order of Os(VIII) > Ru(III). The active species
of catalyst and oxidant have been identified.
Graphical Abstract The kinetic and mechanistic investigations of the reaction between DPC and l-lysine has been studied in presence of microamounts of ruthenium(III) and osmium(VIII) in alkaline medium. The monoperiodatoargentate(III),
Ru(H2O)5OH]2+ and OsO4(OH)2]2− are considered as the active species of oxidant, DPC, ruthenium(III) and osmium(VIII) respectively.
![MediaObjects/10562_2007_9361_Figa_HTML.gif](/content/x1413868p074397l/MediaObjects/10562_2007_9361_Figa_HTML.gif) |
| |
Keywords: | Kinetics Diperiodatocuprate(III) Oxidation l-lysine" target="_blank">l-lysine Osmium(VIII)/Ruthenium(III) catalysis |
本文献已被 SpringerLink 等数据库收录! |