Physicochemical studies on some 1,35-triphenylformazan derivatives and their complexes

ABSTRACT

The stability constants of the complexes formed between divalent Co, Ni, Cu and Zn ions with 1, 3, 5- triphenylformazan derivatives were determined potentiometrically and log Beta [1] and Log Beta[2] values calculated. The relations between the stability constants of the complexes and their ionization potential, electronegativity, ionic radius and atomic number were investigated. The effect of the substituents present on the ligand molecules is also considered, the relationships being treated statistically. The values indicate that Cu-complexes are highly susceptible to the influence of substituents on the one or five positioned phenyl moiety. The values of Delta G, Delta H and Delta S of the complexes are determined. The conductimetric titrations of the above divalent ions with formazan derivatives show breaks at molar ratios 11 and 12 which is in accordance with the results obtained from pH-metric titrations