Biological Activity Studies on Metal Complexes of Macrocyclic Schiff Base Ligand: Synthesis and Spectroscopic Characterization

In this study, we prepared the macrocyclic Schiff base ligand (L) derived from 1,4-dicarbonyl-phenyl-dihydrazide and pentane-2,4-dione (2:2) and its Co-II, Cu-II and Ni-II complexes. The compounds were characterized by the analytical and spectroscopic methods like elemental analysis, molar conductance measurements, mass spectrometry, H-1 nuclear magnetic resonance (NMR), and Fourier transform infrared (FTIR) spectroscopy. The ligand behaves as a tetradentate ligand and coordinates to the metal ions via the nitrogen atoms and the complexes have the mononuclear structures. The analytical and spectroscopic results indicated that the complexes are non-electrolytes in nature and may be formulated as [M(C26H28N8O4)X-2], where M = Co-II, Cu-II and Ni-II and X = Cl-. The antimicrobial activities of the ligand and its complexes, as growth inhibiting agents, have been screened in vitro against different species of bacteria and fungi and the results concluded that the metal complexes are effective drugs against the tested strains as compared to the macrocyclic ligand.