Metal complexes of uridine in solution

Abstract

The stability constants of binary and ternary complexes of Cu^II, Ni^II, Zn^II, Co^II, Mn^II, Mg^II, and Ca^II with uridine as a primary ligand and glycine, histidine, histamine, and oxalic acid as secondary ligands have been determined in aqueous medium by potentiometric pH-titration techniques [I= 0.10 mol dm ^–3(KNO₃) at 35 °C]. In the binary systems the uridine acts as a bidentate ligand involving N(3) and O(4) in metal co-ordination. However, in the ternary systems studied it behaves as a unidentate ligand, bonding only through N(3). These observations are explained on the basis of the dependence of the binding of uridine on the pH of the reaction medium.