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

Abstract

<p>In this study, we prepared the macrocyclic Schiff base ligand (L) derived from 1,4-dicarbonylphenyl- 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, ¹H 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)X₂], 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 <italic>in vitro</italic> 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.</p>