Synthesis, Characterization, DNA Cleavage, and Antimicrobial Studies of Some Transition Metal Complexes With a Novel Schiff Base Derived From 2-Aminopyrimidine

Abstract

Complexes of manganese(II), cobalt(II), nickel(II), copper(II), and zinc(II) with a Schiff base formed by the condensation of 2-aminopyrimidine with 2-hydroxy-1-naphthaldehyde were synthesized and characterized on the basis of elemental analysis, molar conductance, magnetic susceptibility data, UV-vis, IR, FAB mass, and ¹H and ¹³C NMR spectral studies. The Schiff base can exhibit enolimine-quinoneamine tautomerism. In the solid state the ligand existed in the enolimine form. However, in solution it existed in the quinoneamine tautomeric form. But on complexation with the metal ions, the ligand existed in the imine form. The spectral data revealed that the ligand acted as monobasic bidentate coordinating to the metal ions through azomethine nitrogen and deprotonated naphtholate oxygen. Molar conductance values adequately supported the nonelectrolytic nature of the complexes. All the complexes exhibited 1:2 metal-ligand stochiometry. Based on electronic spectral data and magnetic moment values, suitable geometry has been proposed for each complex. The copper(II) complex has been subjected to thermal decomposition studies. The XRD pattern of the copper(II) complex indicated an orthorhombic crystal lattice. The ligand and the metal complexes were screened for their antibacterial and antifungal activities by disc diffusion method. DNA cleavage efficiency of the ligand and the complexes were monitored by gel electrophoresis method.

Keywords:

• 2-aminopyrimidine
• antibacterial
• antifungal
• DNA
• Schiff base
• XRD

Acknowledgments

The authors express our sincere thanks to Prof. Dr. G. M. Nair and Dr. V. Jayakumaran Nair, Department of Biotechnology, University of Kerala, Kariavattom Campus, Trivandrum, for providing facilities for biocidal studies.