Synthesis, characterization, antimicrobial, DNA binding, and oxidative cleavage activities of Cu(II) and Co(II) complexes with 2-(2-hydroxybenzylideneamino)isoindoline-1,3-dione

Abstract

(E)-2-(2-hydroxybenzylideneamino)isoindoline-1,3-dione (Hbid) was prepared by condensation of N-aminophthalimide and salicylaldehyde and characterized by elemental analysis, IR, ¹H-NMR, and mass spectral studies. Mononuclear complexes [(phen)Cu^II(μ-Hbid)₂H₂O] (1), [(phen)Co^II(Cl)₂(μ-Hbid)]6H₂O (2) (phen = 1,10-phenanthroline) and binuclear complexes [Cu^II(μ-Hbid)]₂ (3), and [Co^II(μ-Hbid)]₂ (4) with Hbid were prepared and characterized by elemental analysis, IR, UV-Vis, molar conductance, and thermogravimetric (TG) techniques. DNA-binding properties of 1–4 were investigated by UV spectroscopy, fluorescence spectroscopy, and viscosity measurements. The results suggest that 1 and 2 bind to DNA by partial intercalation, whereas 3 and 4 find different groove-binding sites. The cleavage of these complexes with super coiled pUC19 has been studied using gel electrophoresis; all the complexes displayed chemical nuclease activity in the absence and presence of H₂O₂ via an oxidative mechanism. Complexes 1–4 inhibit the growth of both Gram-positive and Gram-negative bacteria.

Keywords:

• 2-(2-Hydroxybenzylideneamino)isoindoline-1,3-dione
• Cu(II)/Co(II) complexes
• DNA binding
• Gel electrophoresis
• Antimicrobial activity

Acknowledgments

One of the authors, HDR, is grateful to the University of Mysore for providing minor research project. The other author, LSK, is grateful to the UGC, New Delhi, for the award of Rajiv Gandhi National Fellowship. They thank the Head of the Department of Biotechnology for providing help in carrying out antimicrobial and nuclease activities.