Physicochemical studies on some isatin isonicotinoyl hydrazone complexes prepared at PH 10

The complexes of Co, Ni, Pd, Cu and Cd of isatin isonicotinoyl hydrazone [HL] were prepared at pH 10 and characterized by elemental analysis and different physical techniques. Magnetic and spectral data suggested octahedral structures for Cu and Ni complexes, but tetrahedral for the Co complex. The dissociation constant pK of the ligand has been determined spectrophotometrically. The DC electrical conductivity of the compressed powder samples was investigated as a function of temperature. The activation energy [delta Eg] was calculated for the ligand and complexes which showed that the ligand has lower delta Eg than the complexes. The magnitudes of delta Eg were correlated with the number of d-electrons of the transition metal ion

Isatin isonicotinoyl hydrazone complexes of Zn, Cd and Hg

The Zn, Cd and Hg complexes of isatin isonicotinoyl hydrazone were prepared at two different pH. Their structures were confirmed by elemental analysis, IR, PMR spectroscopy and TG studies. Only hydrate bis complexes were obtained, which are insoluble in most organic solvents and have melting points above 270C. They have the formula [M[HL]2. Cl2]xH2O, however, the mercuric complex obtained from a solution of pH 10 has the formula HgL2.3H2O. X-ray diffraction patterns revealed less crystallinity for the Zn complex prepared at pH 10, than that obtained from neutral medium. The ligand and the Cd and Hg complexes are biologically active towards Gram +ve and Gram -ve bacteria, but the complexes of Zn are inactive