Ruthenium(III) Catalyzed Oxidation of Hypoxanthine and Xanthine by Mn(VII) in Aqueous Brønsted Acid Solutions: A Kinetic and Mechanistic Study

Abstract

Mn(VII) is broadly utilized as an oxidizing specialist, however it couldn’t oxidize hypoxanthine (HXAN) and xanthine (XAN) even in concentrated Brønsted acidic (HClO4, H2SO4) media and at raised temperatures. In any case, the responses went through flawlessly in presence of millimolar arrangements of ruthenium chloride (Ru(III) or RuCl3) in presence of fluid Brønsted acidic arrangements. Under synergist conditions, response complied with first request energy in [(Mn(VII)] and [Alkaloid] at steady causticity and temperature. Increase in [Ru(III)] dramatically sped up the reactions with a first order dependence on [catalyst] at constant acidity and temperature. The rate of oxidation was enhanced by an increase in the concentration of Brønsted acid (HClO4, H2SO4). The rate increases observed were examined using the acidity function criteria of Zucker-Hammett, Bunnett and Bunnett-Olsen. The most logical mechanism, involving the involvement of the water molecule in the slow step, has been proposed based on observed Bunnett-Olsen criteria of acidity functions (as proton transferring agent).