Metal complexes of 2-hydroxynaphthylazoantipyrine

Abstract

Equilibria between 2-hydroxynaphthylazoantipyrine and protons or bivalent transition metal ions have been investigated potentiometrically at 25±0.1°C in 0.1 M NaNO3 solutions. The experimental data were fitted assuming the formation of 1:1 and 1:2 complex species and their formation constants were calculated using the non-linear least square computer program MINIQUAD. The solid complexes of Cu(II), Co(II), Ni(II), UO2(VI) and Pd(II) have been prepared and characterized by elemental analyses, conductance, spectral and magnetic measurements. It has been found that 1:2 (metal : ligand) complexes were formed with Ni(II) and Co(II) and 1:1 complexes with Cu(II), Pd(II) and UO2(VI). Coordination seems to occur with the metal ion through the phenolic oxygen, carbonyl oxygen and azo nitrogen atoms.