Potentiometric investigation of ternary complexes of nickel, copper, zinc and cadmium with L-alpha-alaninehydroxamic acid and ethylenediamine

Mixed-ligand complex formation of M(II) (M = Ni, Cu, Zn and Cd) with 1-alpha-alaninehydroxamic acid (alpha-Alaha) as primary ligand (A) and ethylenediamine (en) as secondary ligand (B) have been determined potentiometrically [298 K, mu=0.2 (KCl)]. Formation constants for binary systems involving L-alpha-alaninehydroxamic acid or ethylenediamine were determined under identical experimental conditions and pH-titration data were analysed using the SUPERQUAD computer program. The relative stability of each ternary complex was compared with that of the corresponding binary complexes in terms of Delta log K and log X values.