DNA interaction studies of a platinum(II) complex, PtCl2(NN) (NN = 4,7-dimethyl-1,10-phenanthroline), using different instrumental methods

The Pt(II) complex, PtCl2(4,7-Me2phen) (4,7-Me2phen = chelating dinitrogen ligand: 4,7-dimethyl-1,10-phenanthroline) was synthesized and characterized by spectroscopic (1H, 13C NMR) and elemental analysis techniques. Binding interaction of this complex with calf thymus (CT) DNA has been investigated by emission, absorption, circular dichroism, viscosity and DNA thermal denaturation studies. The complex displays significant binding properties to the CT DNA. In fluorimeteric studies, the binding mode of complex with CT DNA was studied by using methylene blue as a fluoresce probe. As evidenced by the increasing fluorescence of methylene blue–DNA solutions in presence of increasing amount of complex, PtCl2(NN) complex is able to displace the methylene blue intercalated into DNA completely as to indicate intercalation. Furthermore, mentioned complex induces detectable changes in the CD spectrum of CT-DNA, an increase in Tm value, and an increase in its viscosity. The experimental results showed that Pt(II) complex bound to DNA by an intercalative mode of binding.