METAL-COMPLEXES OF 2-HYDROXYNAPHTHYLAZOANTIPYRINE

Equilibria between 2-hydroxynaphthylazoantipyrine and protons or bival ent transition metal ions have been investigated potentiometrically at 25+/-0.1 degrees C in 0.1 M NaNO3 solutions. The experimental data we re fitted assuming the formation of 1:1 and 1:2 complex species and th eir formation constants were calculated using the non-linear least squ are computer program MINIQUAD. The solid complexes of Cu(II), Co(II), Ni(II), UO2(VI) and Pd(II) have been prepared and characterized by ele mental analyses, conductance, spectral and magnetic measurements. It h as been found that 1:2 (metal :ligand) complexes were formed with Ni(I I) and Co(II) and 1:1 complexes with Cu(II), Pd(II) and UO2(VI). Coord ination seems to occur with the metal ion through the phenolic oxygen, carbonyl oxygen and azo nitrogen atoms.