Phenoxo-bridged symmetrical homobinuclear complexes derived from an “end-off” compartmental ligand, 2,6-bis[5′-chloro-3′-phenyl-1H-indole-2′-carboxamidyliminomethyl]-4-methylphenol

Abstract

A compartment ligand 2,6-bis[5′-chloro-3′-phenyl-1H-indole-2′-carboxamidyliminomethyl]-4-methylphenol was prepared and homobinuclear phenol-bridged Cu(II), Ni(II), Co(II), Zn(II), Cd(II), Hg(II), Fe(III), and Mn(II) complexes have been prepared by the template method using the precursors 2,6-diformyl-4-methylphenol, 5-chloro-3-phenylindole-2-carbohydrazide and metal chlorides in 1 : 2 : 2 ratio, respectively. The complexes were characterized by elemental analyses, conductivity measurements, magnetic susceptibility data, IR, NMR, FAB mass and ESR spectra, TGA, and powder XRD data. Cu(II), Co(II), Zn(II), Cd(II) and Hg(II) complexes exhibit square pyramidal geometry whereas Ni(II), Mn(II), and Fe(III) complexes are octahedral. Low magnetic moment values for Cu(II), Ni(II), Co(II), Fe(III), and Mn(II) complexes show antiferromagnetic spin-exchange interaction between two metal centers in binuclear complexes. The ligand and its complexes were tested for antibacterial activity against Escherichia coli and Staphyloccocus aureus, and antifungal activity against Aspergillus niger and Candida albicans.

Keywords:

• Binuclear complexes
• “End-off” compartmental ligand
• Phenoxo-bridged complexes

Acknowledgments

The authors are thankful to the Chairman, Department of Chemistry, Gulbarga University, Gulbarga for providing the facilities. They also thank NMR Research Centre, Indian Institute of Science, Bangalore, SAIF, Sophisticated Test and Instrumentation Centre, Kochi and SAIF, Central Drug Research Institute, Lucknow, for ¹H NMR, ESR, FAB mass, TGA, and elemental analysis data.