Synthesis, crystal structures and CT-DNA/BSA binding properties of Co(III) and Cu(II) complexes with bipyridine Schiff base ligand

Abstract

A novel bipyridine Schiff base ligand C12H9ClN4O (HL) and its two transition metal complexes [CoL2]NO3⋅H2O (1) and CuL2⋅CH3OH (2) have been synthesized. Their structures have been characterized by single crystal XRD, showing that 1 and 2 belong to triclinic systems and P-1 space groups. TG-DTG results indicate that 1, 2 and HL all possess high thermal stabilities. The interactions of 1, 2 and HL with calf thymus DNA (CT-DNA) have been investigated by UV–vis spectra and fluorescence spectra, illustrating each complex binds to CT-DNA in an intercalation mode and HL interacted with CT-DNA through groove binding mode. Fluorescence spectroscopy has been used to determine the interactions of 1, 2 and HL with BSA, showing 1, 2 and HL can bind with BSA in static mechanism. Microcalorimetry measurements indicate that the processes of 1, 2 and HL interacting with CT-DNA and BSA are all exothermic, and the reactions complete within 35 min. The molecular docking shows that each compound binds to CT-DNA and BSA mainly through hydrophobic interactions and hydrogen bonds. In addition, 2 exhibits excellent antibacterial activities against Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis and Escherichia coli.