Speciation of the ternary complexes formed between copper(II), salicylic acid and small blood serum bioligands

In this work we present the speciation of the ternary complexes formed between the copper(II)-salicylate (Sal2 −) system and the small blood serum bioligands, such as lactate (Lac−), oxalate (Ox2 −), citrate (Cit3 −) and phosphate (PO43 −). The speciation of the ternary systems were studied by pH-potentiometry at 25 °C and using an ionic strength I = 1.0 mol·dm−3 KNO3. In the Cu(II)-Sal2 − − Lac− system the complexes [Cu(Sal)(Lac)(OH)]2 −, [Cu(Sal)(Lac)(OH)2]3 − and [Cu(Sal)2(Lac)]3 − were detected. In the case of the Cu(II)-Sal2 −-Ox2 − system the complexes [Cu(Sal)(Ox)]2 −, [Cu(Sal)(Ox)(OH)]3 − and [Cu(Sal)(Ox)(OH)2]4 − were observed. In the Cu(II)-Sal2 − − Cit3 − system the species [Cu(Sal)(H2Cit)]−, [Cu(Sal)(HCit)]2 −, [Cu(Sal)(Cit)]3 − and [Cu(Sal)(Cit)(OH)]4 − were detected and in the Cu(II)-Sal2−-PO43 − system the complexes [Cu(Sal)(H2PO4)]−, [Cu(Sal)(HPO4)]2 − and [Cu(Sal)(PO4)]3 − were observed.