Novel copper (II) binary complexes with N,O-donor isoxazole Schiff base ligands: Synthesis, characterization, DPPH scavenging, antimicrobial, and DNA binding and cleavage studies

Abstract

Cu(II) binary complexes of the type [Cu(Ln)2], where n = 1–3, HL1 = 2-((E)-(3,5-dimethylisoxazol-4-ylimino)methyl)-6-tert-butylphenol (C1), HL2 = 2-((E)-(3,5-dimethylisoxazol-4-ylimino)methyl)-4-bromo-6-methoxyphenol (C2), HL3 = 2-((E)-(3,5-dimethylisoxazol-4-ylimino)methyl)-5-methylphenol (C3) have been synthesized and characterized by analytical, structural, and spectral methods. The antioxidant studies of novel Cu(II) complexes revealed, significant activity against DPPH radical. The synthesized compounds were monitored for antimicrobial activities and the results of these studies indicated that the complexes exhibit a good antimicrobial efficiency compared to ligands. The interaction of CT–DNA with the Cu(II) complexes has been explored using absorption and emission spectral techniques. Spectral evidence showed the intercalative mode of DNA binding with the complexes. Agarose gel electrophoresis results revealed that all Cu(II) complexes induced double strand breaks of pBR 322 plasmid DNA in the presence of H2O2 and UV light.

Keywords

• Isoxazole Schiff base
• Cu(II) binary complex
• Crystal structure
• Antioxidant activity
• Antimicrobial activity
• DNA interaction