Synthesis, spectroscopic studies, and antibacterial activities of 14-membered tetraazamacrocyclic complexes of divalent transition metal ions

Abstract

A new series of macrocyclic complexes, [M(C₄₈H₃₂N₄)X₂], where M = Co(II), Ni(II), Cu(II), and Zn(II); X = Cl⁻, NO₃ ⁻, CH₃COO⁻, have been synthesized by condensation of 1,8-diaminonaphthalene and benzil, in the presence of divalent metal salts in methanolic medium. The complexes have been characterized by elemental analyses, conductance measurements, magnetic measurements, and electronic, NMR, IR, and MS spectral studies. The low value of molar conductance indicates the presence of non-electrolytes. A distorted octahedral geometry is proposed for the complexes. The metal complexes were also tested for their in vitro antibacterial activities against some bacterial strains and compared with the standard antibiotic Ciprofloxacin. Some tested complexes show good antibacterial activities against some bacterial strains.

Keywords:

• Antibacterial activity
• Benzil
• Macrocyclic complexes
• MIC

Acknowledgments

D.P. Singh thanks the University Grants Commission, New Delhi, for providing financial support in the form of Major Research Project [MRP-F.No. 32-196/2006(SR)] and Krishan Kumar for the award of Project Fellowship under the above project. Thanks are also due to the authorities of N.I.T., Kurukshetra, for providing the necessary research facilities.