Synthesis, characterization, DNA binding and cleavage properties of a ternary copper(II) Schiff base complex

A ternary coordination complex 2Cu(C14H8NO3Cl)(C12H8N2)·3CH3OH of a Schiff base (C14H8NO3Cl: 4-chloroanthranilic acid–salicylaldehyde) was synthesized from 4-chloroanthranilic acid, salicylaldehyde, copper acetate and 1,10-phenanthroline and characterized by physicochemical and spectroscopic methods. X-ray crystallography shows that the copper atom is five coordinated by the imine nitrogen, two nitrogen atoms from 1,10-phenanthroline, the hydroxyl oxygen and the carboxylate oxygen atom. The interaction of the complex with calf-thymus DNA was investigated by UV absorption spectroscopy, fluorescence emission spectroscopy and viscosity. In addition, the cleavage reaction with pBR322 supercoiled plasmid DNA was investigated. The complex binds to DNA and also exhibits significant DNA cleavage activity.