Nickel(II) and Cobalt(II) Complexes with Symmetrical Four-Dentate Ligands: Crystal Structures, Characterization, and Initial DNA Binding Mechanism Research

Abstract

Four new nickel(II) and cobalt(II) complexes of Schiff base ligands: [Ni(L)Cl2]·2H2O (I), [Ni(L)(H2O)2] (NO3)2 (II), [Ni(L)(H2O)2] (ClO4)2 (III), and [Co(L) (H2O)2] (NO3)2 (IV) (L = 1,3-[bis(pyridine-2-imino)]propane) have been synthesized. The four complexes have been fully characterized by elemental analysis, IR, absorption spectra, emission spectra, and single-crystal X-ray diffraction analysis. The binding of the four complexes to calf thymus DNA (CT DNA) has been investigated by absorption spectra and emission spectra. The results of the two methods indicate that the action mode of complex I with DNA is intercalative mainly, and the action mode of complexes II, III, IV with DNA cannot be concluded, it should be sustained by other experimental measurements. Four new nickel(II) and cobalt(II) complexes of Schiff base ligands: [Ni(L)Cl2]·2H2O (I), [Ni(L)(H2O)2] (NO3)2 (II), [Ni(L)(H2O)2] (ClO4)2 (III), and [Co(L) (H2O)2] (NO3)2 (IV) (L = 1,3-[bis(pyridine-2-imino)]propane) were synthesized and their crystal structures were determined. The binding of the four complexes to calf thymus DNA (CT DNA) has been investigated.