CONICET | Buscador de Institutos y Recursos Humanos

Vanadium is found in different oxidation states, in about 65 minerals and in carbon deposits. It has been determined that vanadium(IV) and vanadium(V) interact with many molecules in the biological systems. Inside the cell, vanadium (IV) can potentially interact with carboxylate, phosphate and amine groups of the biomolecules. In the last years, they have been synthesised some organic and inorganic complexes of great value in diabetes treatments. Besides, some complexes are used in experimental models as antitumoral agents. Taking into account the growing interest in vanadium interactions with different ligands, and the multiple metal ion oxidation states, it is necessary a detailed understanding of the redox reactions of vanadium(V) with some ligands of living organisms. We study the kinetics of oxidation of 2-alpha-hydroxyacids, as L(+)-tartaric acid and D-glucono-1,5-lactone, by action of V(V). The redox reactions involves kinetic studies at low pH, intermediates and products detection and the formation equilibria of V(V)-substrate complex. The kinetics were carried out by monitoring the V(V) consumption at 350 nm and the formation of V(IV) at 760 nm. In order to provide the reaction mechanisms, the effect of substrate, vanadium and acid concentrations has been analysed, at constant ionic strength and temperature. The presence of free radicals has been detected with acrylamide in the course of the reaction. The kinetic profiles were adjusted considering a sequence of reactions of the type V(V)®V(V)-S®VO2+. The results will serve as model system in the search of simple vanadium complexes with biological relevance.