Synthesis and Characterization of First Row Transition Metal Complexes of a Schiff Base Hydrazone Containing Quinoxaline Moiety

A series of new chromium(III), manganese(II), iron(III), cobalt(II), nickel(II) and copper(II) complexes of the Schiff base hydrazone (HDHAHQO), synthesized from 3-hydrazino quinoxaline-2-one (HQO) and dehydroacetic acid (DHA) were prepared and characterized. The Schiff base exhibits biambidenticity. It behaves as a monobasic tridentate ONN donor in iron(III) and copper(II) complexes and ONO donor in chromium(III), manganese(II), cobalt(II) and nickel(II) complexes. The nature of bonding and the stereochemistry of the complexes have been deduced from elemental analyses, thermal, infrared, electronic spectra, magnetic susceptibility and conductivity measurements. An octahedral geometry was suggested for all the complexes. The Schiff base ligand, HDHAHQO, and its complexes were tested against one strain Gram+ve bacteria (Staphylococcus aureus), Gram-ve bacteria (Escherichia coli). The prepared metal complexes exhibited higher antibacterial activities than the parent ligand.