Synthesis, characterization and DNA-binding properties of zinc(II) and nickel(II) Schiff base complexes

A new ligand, 2-carboxybenzaldehyde-(4'-hydroxy)benzoylhydrazone(H2L) and its Zn-II and Ni-II complexes have been synthesized and characterized on the basis of elemental analyses, molar conductivities, H-1-NMR, IR spectra and thermal analyses. In addition, DNA-binding properties of these two metal complexes were investigated using spectrometric titrations, ethidium bromide displacement experiments, and viscosity measurements. The results show that the two complexes, especially the Ni-II complex, strongly bind with calf-thymus DNA, presumably via an intercalation mechanism. The intrinsic binding constants of the Zn-II and Ni-II complexes with DNA are 2.46 x 10(5) and 7.94 x 10(5) M-1, respectively.