Synthesis, characterization, antimicrobial, DNA-cleavage and antioxidant activities of 3-((5-chloro-2-phenyl-1H-indol-3-ylimino)methyl)quinoline-2(1H)-thione and its metal complexes

•Synthesis, characterization, antimicrobial, DNA-cleavage and antioxidant activities of ligand and its metal complexes.•The stoichiometry of Cu(II) and Ni(II) complexes is M:L and Co(II), Zn(II) and Fe(III) complexes showed M:L2.•The ESR data of Cu(II) complex proves square planar geometry.•Cu(II), Co(II), Zn(II) and Fe(III) complexes cleave calf-thymus DNA except Ligand HL and Ni(II) complex.

Schiff base 3-((5-chloro-2-phenyl-1H-indol-3-ylimino)methyl)quinoline-2(1H)-thione and its Cu(II), Co(II), Ni(II), Zn(II) and Fe(III), complexes have been synthesized and characterized by elemental analysis, UV–Visible, IR, 1H NMR, 13C NMR and mass spectra, molar conductance, magnetic susceptibility, ESR and TGA data. The ligand and its metal complexes have been screened for their antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa, antifungal activity against Aspergillus niger and Aspergillus flavus in minimum inhibition concentration (MIC) by cup plate method respectively, antioxidant activity using 1,1-diphenyl-2-picryl hydrazyl (DPPH), which was compared with that of standard drugs vitamin-C and vitamin-E and DNA cleavage activity using calf-thymus DNA.

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