Asymmetric bis(bidentate) azine ligand and transition metal complexes: Synthesis, characterization, DNA-binding and cleavage studies and extraction properties for selected metals and dichromate anions

Abstract

New bis(bidentate) azine NNN'N' donor ligand was prepared by linking (1Z,1'Z)-1,1'-{propane-1,3-diylbis[oxybenzene-4,1-diyl(1Z)eth-1-yl-1-ylidene]} dihydra-zine to pyridine-2-carbaldehyde. Two kinds of copper(II) and nickel(II) complexes with different stoichiometries were prepared. Reaction of bis(azine) ligand with Cu(II) and Ni(II) chloride with 1:1 molar ratio gave azine complexes with stoichiometry [M(L)Cl2] while 2:1 molar ratio reaction of Cu(II) and Ni(II) chloride with bis(azine) composed binuclear copper complexes with general stoichiometry [M2(L)Cl4]. The structures of both bis-azine ligand and its complexes were identified by elemental analysis, infrared spectra, UV-Vis electronic absorption spectra and magnetic susceptibility measurements, TGA and powder XRD. DNA binding and DNA cleavage activities of the synthesized metal complexes were examined by using UV-vis titration and agarose gel electrophoresis, respectively. The results indicate that all the complexes bind significantly calf thymus DNA and cleavage pBR322 DNA. Furthermore, the complexing properties of the bis-azine ligand toward selected transition metal cations and dichromate anions were also reported.