Mixed ligand complex formation by nickel(II) ion

Abstract

Nickel(II) forms mixed complexes, NiAB, NiA₂B, and NiAB₂, containing two different types, A and B, of ligand molecule, with each of the three possible pairs of the ligands ethylenediamine, histamine, and serine anion. The stability constants of the mixed complexes have been computed from pH titration data. In all three systems containing equimolar mixtures of nickel(II) and the two ligands, the complex NiAB is a major species, and the other mixed complexes are present in smaller amounts. However, appreciable concentrations of the corresponding 1:1:2 or 1:2:1 complexes are formed if the proportion of either ligand is increased in any mixture.