Synthesis, Spectral Characterization, Thermokinetics and Biological Studies of Co(II), Ni(II), Cu(II), Zn(II) and Zr(IV) Complexes Derived from Hydrazone Schiff Base

Mononuclear Co(II), Ni(II), Cu(II), Zn(II) and Zr(IV) complexes with new bidentate Schiff base ligand 2-hydroxy-N’-(2-oxoindolin-3-ylidene)benzohydrazide (LH2) were synthesized and the complexes were characterized by elemental analysis, IR, FAB-mass, molar conductivities, magnetic measurements, electronic spectra and thermal analysis. The Cu(II) complex was additionally characterized by ESR study. The ligand behaves as a monobasic bidentate ligand, coordinating through azomethine Nitrogen and the deprotonated Oxygen atom. Analytical data suggested 1:2 (metal: ligand) mole ratio for all the complexes. The low molar conductance values of the all metal complexes in DMSO reveal their non-electrolytic nature. The physicochemical data suggested an octahedral geometry for Zn(II) and Zr(IV) complexes, distorted octahedral geometry for Cu(II), whereas square planar geometry for Co(II) and Ni(II) complexes. The thermodynamic analysis showed that the complexes loose hydrated and/or coordinated water molecules in the first step followed by decomposition of ligand moiety in the further steps leading to formation of stable metal oxide. The antibacterial as well as antifungal activities of the ligand and its metal complexes were evaluated.