Synthesis, physicochemical studies and biological evaluation of unimetallic and heterobimetallic complexes of hexadentate dihydrazone ligands

Abstract

A new coordination unimetallic and heterobimetallic complexes of hexadentate N2O4 donor dihydrazone ligands were prepared by the condensation of 4-formyl antipyrine with adipic dihydrazide and succinic dihydrazide. The ligands (1) and (11) and their complexes thoroughly characterized using various analytical, physical and spectroscopic techniques, which indicate a distorted octahedral geometry around the metal ions. The ESR spectra of solid copper(II) complexes (2–4) and (12–14) showed axial symmetry with g||>g⊥ > ge, indicating distorted octahedral structure and the presence of the unpaired electron in a d(x2−y2) orbital with significant covalent bond character. The antimicrobial activity results of the metal compounds (2–5), (7), (10), (12–15) and (17) show that, all these complexes exhibit inhibitory moderate to mild effects towards Bacillus subtilis, Escherichia coli and Aspergillus niger.

Keywords

• IR
• Dihydrazone
• Antipyrine
• EPR
• Adipohydrazide
• Unimetallic and heterobimetallic complexes
• Hexadentate ligand
• Biological activity