Chemical Speciation Study of Ternary Complexes of Cu (II) with Succinic Acid Dihydrazide and Some Amino Acids in Aqueous Solution

Abstract

Solution equilibrium studies on the systems of Cu (II) with succinic acid dihydrazide (SADH) as a primary ligand (L) and selected amino acids (X) as secondary ligand were investigated with a potentiometric titration technique. The formation constants of the complexes were determined at 30 ± 1°C and ionic strength 0.1 mol dm ^-3 NaCl. The formation constants determined, suggests the formation of mixed ligand complexes. The relative stabilities of the ternary complexes are compared with those of the corresponding binary complexes in terms of ΔlogK values. The stability constants were calculated by using MINIQUAD 75 computer program, and species distribution diagrams were produced using the HYSS computer program.  Selection of the best fit chemical models was based on statistical parameters. Distribution diagram and plausible equilibria for the formation of the complex species are presented.

Keywords: stability constant, ternary complex, best fit model, Δlog K