Metal (II) complexes of ono donor schiff base ligand as a new class of bioactive compounds containing indole core: Synthesis and characterization

Abstract

Objective: The present communication deals with the synthesis and characterization of biologically active Cu (II), Co (II), Ni (II) and Zn (II) complexes of ONO donor Schiff base ligand derived from the condensation of 5-methyl-3-phenyl-1H-indole-2-carbohydrazide with 2-hydroxy-1-napthaldehyde. Methods: The chemical structures of the Schiff base ligand and its metal complexes were elucidated by elemental analysis and various physicochemical techniques like IR, 1H NMR, ESI mass, double beam UV-visible spectra, ESR, thermal analysis, powder XRD, conductometric and magnetic susceptibility measurements. Newly synthesized compounds were screened for their antibacterial and antifungal activities. Results: Spectral investigations suggested octahedral coordination geometrical arrangement for Cu (II), Co (II) and Ni (II) complexes, having 1:2 stoichiometric ratio of the type [M(L)2] whereas the tetrahedral coordination geometric arrangement of Zn(II) complex, with 1:1 stoichiometric ratio of the type [Zn(L)Cl]. The antimicrobial activity results revealed that the metal complexes were found to be more active than the free ligand. Furthermore, the DNA cleavage activity was also studied using plasmid DNA pBR322 as a target molecule, and the compounds showed moderate activity. Conclusion: A new Cu (II), Co (II), Ni (II) and Zn (II) complexes were prepared with tridentate ONO donor novel Schiff base ligand (L) and characterized by various physicochemical techniques and all the complexes are found to be non-electrolytic in nature. In addition, all the newly prepared compounds are found to be biologically active. © 2016 The Authors. Published by Innovare Academic Sciences Pvt Ltd.