Abstract

Synthesis, DNA Binding And Photocleavage Studies Of Mixed Ligand Co(III) And Ni(II)Complexes Of Phenanthroline And Naphthyridine

Author(s): Halehatty S.Bhojya Naik, Mustur C.Prabhakara

New Co(III) and Ni(II) mixed ligand complexes of the type [M(phen)2(napy)](PF6)nH2O where M=Co(III) or Ni(II), napy=4-methyl- 1,8 naphthyridin-2-ol, and phen=1,10-phenanthrolines n=3 or 2, x=3 or 2 have been synthesized and characterized by employing analytical and spectralmethods. The DNAbinding property of the complexes (1) and (2) with Calf thymus-DNA have been studied by using absorption spectra, viscosity measurements as well as thermal denaturation studies. The absorption spectral results indicate that the Co(III) and Ni(II) complexes intercalate between the base pairs of the DNA tightly with intrinsic DNA binding constant of 2.2106M-1 and 2.0106M-1 in 5mMTris-HCl/50mM NaCl buffer at pH 7.2, respectively. The large enhancement in the relative viscosity of DNA on binding to the napy supports the proposed DNA binding modes. The oxidative cleavage and photocleavage activity of the complexes (1) and (2) were studied at the concentration of 20-40M. The Co(III) and Ni(II) complexes induced DNA photocleavage at the concentration of 40Mafter irradiation for UV light at 365nm.