Synthesis, characterization, and DNA-binding properties of the cobalt(II) and nickel(II) complexes with salicylaldehyde 2-phenylquinoline-4-carboylhydrazone

Salicylaldehyde 2-phenylquinoline-4-carboylhydrazone (H2L), and its novel cobalt(II), nickel(II) complexes (M center dot HL center dot 3H(2)O)center dot NO3 (M=Co (1), M=Ni (2)), have been synthesized and characterized by elemental analysis, molar conductivity, mass spectra and IR spectra. The interaction of these complexes with calf-thymus DNA was investigated by UV absorption spectroscopy, fluorescence spectroscopy, circular dichroism (CD) spectroscopy, cyclic voltammetry, and viscosity measurements. The two complexes showed absorption hyperchromism in the range of 190-280 nm. The binding constant have been determined using absorption measurement and found to be 0.89 x 10(5) M-1 and 2.2 x 10(5) M-1, respectively. Results suggest that the two complexes bind to DNA via a groove binding mode. (c) 2007 Elsevier B.V. All rights reserved.