Synergistic Antimicrobial and Antioxidant Effects of Indole Schiff Base–Metal (II) Complexes: A Dual Approach

Schiff base of 5-chloro-N'-(4-(dimethylamino)benzylidene)-3-phenyl-1H-indole-2-carbohydrazide and its Cu(II), Co(II), Ni(II), and Zn(II) complexes have been synthesized. The structures of newly synthesized molecules were characterized by various spectroscopic techniques and elemental analysis. The electron spin resonance (ESR), electronic spectra, magnetic susceptibility, and TGA suggested octahedra geometry for the synthesized Cu(II), Co(II), Ni(II), and Zn(II) complexes with 1:2 stochiometric ration. Amide carbonyl's oxygen atom and nitrogen of azomethine of the Schiff base are the bonding sites. The minimum inhibitory concentration (MIC) approach was adopted to test for antibacterial and antifungal activities to assess the antimicrobial efficacy of the ligand and its metal complexes. The results exhibited good to moderate activity. Cu(II), Co(II), and Ni(II) complexes have demonstrated good free radical scavenging activity among the compounds under investigation, while the Zn(II) complex and ligand L have demonstrated good to moderate action. As demonstrated by the cleavage of calf-thymus DNA, it can be concluded that all of the compounds under investigation prevented the growth of pathogenic organisms by DNA cleavage based on the result cleavage of DNA seen in the case of ligand L and its Cu(II), Co(II), Ni(II), and Zn(II) complexes.