Kinetics and mechanism of oxidation of L-arginine by diperiodatonickelate(IV) in aqueous alkaline medium

P. G. Department of Studies in Chemistry, Karnatak University, Dharwad-580 003, India

Manuscript received 31 March 1998, revised 9 July 1998, accepted 20 July 1998

Oxidation of L-arginine by diperiodatonickelate(lv) (DPN) in aqueous alkaline medium is first order in [DPN], but fractional order each in [L-Arg] and [OH^-]. The rate of reaction decreases in the decrease in the dielectric constant of the medium. Added products and variation of ionic strength have no significant effect on the rate of the reaction. A mechanism involving the formation of an intermediate complex between oxidant and substrate has been proposecd. The rate and equilibrium constants involved in the mechanism and the activation parameters for the slow step have been determined.