Equilibrium studies of some Ni(II) ternary complexes: A comparative study

pH-metric method has been used to find out log K-MAL(MA) at 25 +/- 0.1 degreesC and at constant ionic strength, mu = 0.2 M (NaClO4), where A = 2,2'-bipyridyl, 2-2'-bipyridylamine, or o-phenanthroline and L = glycollic acid, lactic acid or malic acid. The coordinating tendencies of various ligands depend on the basicities of the ligand, size of the ligand and chelate ring of the ligand. It is found that along with size of secondary ligand, primary ligand size also plays a deciding role in the stability of mixed ligand complexes. Also an attempt is made to correlate the coordinating tendencies of (O) over bar-(O) over bar, N-(O) over bar and (O) over bar -S donor atoms as secondary ligands.