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

Abstract The complex species formed between vanadium(III)–salicylic acid (H 2 sal) and the small blood serum bioligands: lactic (Hlac), oxalic (H 2 ox), citric (H 3 cit) and phosphoric (H 3 PO 4 ) acids in aqueous solution were studied by means of electromotive force measurements emf (H) at 25 °C and 3.0 mol·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)–H 2 sal–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)–H 2 sal–H 2 ox system; the complexes V(sal)(H 2 cit), [V(sal)(Hcit)] − , [V(sal)(cit)] 2 − and [V(sal)(cit)(OH)] 3 − in the vanadium(III)–H 2 sal–H 3 cit system and the species V(sal)(H 2 PO 4 ), [V(sal)(HPO 4 )] − and [V(sal)(PO 4 )] 2 − were detected in the vanadium(III)–H 2 sal–H 3 PO 4 system. The corresponding stability constants were estimated.