DNA binding and DNA cleavage studies of a water soluble cobalt(II) complex containing dinitrogen Schiff base ligand: The effect of metal on the mode of binding

Binding interaction of a water soluble cobalt(II) complex of a Schiff base, SF, (SF = N,N'-bis(5-[(triphenylphosphonium chloride)-methyl] salicylidine)-o-phenylenediamine) with calf thymus DNA (CT-DNA) has been investigated. The intrinsic binding constant (K-b = 5 x 10(4) M-1) was determined. In comparison with previous study the results indicate that the binding affinity of SF is stronger than its Co(II) complex. Multi-spectroscopic experiments reveal that the binding modes of Co(II) complex in comparison with SF are different; SF may be intercalating between DNA base pairs while its Co(II) complex most likely interact with DNA in an electrostatic binding mode. (C) 2010 Elsevier Masson SAS. All rights reserved.