Abstract

SYNTHESIS AND CHARACTERIZATION AND CYCLIC VOLTAMMETRIC STUDIES ON TRANSITION METAL COMPLEXES OF 2,4- DIHYDROXYACETOPHENONE NICOTINOYLHYDRAZONE

A. Suseelamma, K. Raja and M. Swetha*

ABSTRACT

A new series of Cu(II), Ni(II), Co(II), Fe(II) complexes of nicotinoylhydrazone (H2L) was synthesized and characterized by elemental analysis, IR, UV–Vis and ESR spectroscopy, magnetic and conductivity measurements. Electrochemical behaviour of these complexes has been studied by cyclic voltammetry. The spectral data showed that the ligand behaved as a neutral bidentate in complex 1 and monobasic bidentate in complexes 2, 3 and 4, and was bonded to the metal ions via the carbonyl oxygen atom in the ketonic or enolic form, the azomethine nitrogen atom and the deprotonated phenolic hydroxyl oxygen. The ESR spectrum of the solid copper(II) complex showed an axially anisotropic spectrum in the low field region and with g┴> g|| relationships, which is characteristic of a distorted octahedral structure with a dx2-y2 ground state. The copper(II) complexes showed an axial symmetry type with g|| > g┴> ge, indicating a covalent bond character. The electrochemical data of metal complexes indicates that metal complexes exhibit the reversible nature.

Keywords: Metal complexes, synthesis, characterization, nicotinoylhydrazones, cyclic voltammetry.