O-HYDROXY AROYL-ISONICOTINOYL HYDRAZONES AS CHELATING-AGENTS FOR SOMEBIVALENT TRANSITION-METAL IONS

Two series of bivalent metal complexes of the type M(Sal - 2H) .xH(2)O and M(Naph - 2H) have been synthesized, where M : Co, Ni, Cu, Zn, Pd and Cd ions, Sal and Naph are salicylaldehyde and o-hydroxynaphtaldehy de isonicotinoyl hydrazones which acted as dibasic terdentate ligands. The polymeric nature and coordination sites have been characterized b y elemental, (DTA and TGA) thermal analyses, molar conductance, pH, ro om temperature magnetic susceptibility and spectral (IR, H-1 - NMR, UV ) measurements. The protonation constants of the ligands have been det ermined potentiometrically at different temperatures, ionic strengths and at different ethanol-water compositions.