Synthesis, characterization and electrical conductivity of some bivalent metal complexes of ONS donor ligand

Abstract

The solid complexes of VO IV , Mn II , Fe II , Co II , Ni II , Cu, Zn II and Cd with a new tridentate ligand 3-{(1E)-N-(benzylthio)carbonothioyl]ethanehydrazonoyl}-4-hydroxybenzoic acid derived from 5-carboxy-2-hydroxyacetophenone and S-benzyldithiocarbazate, have been synthesized and characterized by analytical, magnetic susceptibility measurements, molecular weight determination, IR and electronic spectra and thermal analysis. From the analytical and thermal data the stoichiometry of the complexes has been found to be 1: 1. (metal: ligand). The molar conductivity data show them to be non-electrolytes. IR spectral data suggest that the ligand behaves as a dibasic tridentate with ONS donor sequence towards metal ions. TGA showed the presence of coordinated water molecules in all chelates except VO IV and Cu II . The solid state electrical conductivity of the complexes are found to be low with σ in the range of 10 -11 10 -7 Ω -1 cm -1 , however the conductivities of all complexes increases as the temperature increases from 313 to 403 K, indicating their semiconducting behaviour. The electrical activation energies of the complexes, which were in the range 0,260 to 0.712 eV, were calculated from Arrhenius plots.