Ternary complex formation between vanadium(III) salicylic acid and small blood serum bioligands

Abstract

The complex species formed between vanadium(III)–salicylic acid (H2sal) and the small blood serum bioligands: lactic (Hlac), oxalic (H2ox), citric (H3cit) and phosphoric (H3PO4) acids in aqueous solution were studied by means of electromotive force measurements emf (H) at 25°C and 3.0mol·dm−3 KCl as ionic medium. Data analysis using the least-squares program LETAGROP taking into account the hydrolytic products of vanadium(III) and the formed binaries complexes indicated the formation of V(sal)(lac) complexes, [V(sal)(lac)(OH)]− and [V(sal)(lac)(OH)2]2− in the vanadium(III)–H2sal–Hlac system. Species V(sal)(Hox)+, [V(sal)(ox)]− were also detected. [V(sal)(ox)(OH)]2−, [V(sal)2(ox)]3− and [V(sal)(ox)2]3− were observed in the vanadium(III)–H2sal–H2ox system; the complexes V(sal)(H2cit), [V(sal)(Hcit)]−, [V(sal)(cit)]2− and [V(sal)(cit)(OH)]3− in the vanadium(III)–H2sal–H3cit system and the species V(sal)(H2PO4), [V(sal)(HPO4)]− and [V(sal)(PO4)]2− were detected in the vanadium(III)–H2sal–H3PO4 system. The corresponding stability constants were estimated.