Novel complexes of Co(III) and Ni(II) containing peptide ligands: Synthesis, DNA binding and photonuclease activity

The new cobalt(III) and nickel(II) complexes of the type [M(L)(2)(H2O)(2)](n+) (where M = Co(III) or Ni(II) ion, n = 3 for Co and 2 for Ni, L = peptides Fmoc. Ala-val-OH (F-AVOH), Fmoc-Phe-Leu-Ome (F-PLOMe) and Z-Ala-Phe-CO-NH2 (Z-APCONH(2))) were synthesized and structurally characterized by FTIR, H-1 NMR, elemental analysis and electronic spectral data. An octahedral geometry has been proposed for all the synthesized Co(III) and Ni(II) metal complexes. The binding property of the complexes with CT-DNA was studied by absorption spectral analysis, followed by viscosity measurement and thermal denaturation studies. Detailed analysis revealed that the metal complexes intercalates into the DNA base stack as intercalator. The photo induced cleavage studies shows that the complexes possess photonuclease property against pUC19 DNA under UV-Visible irradiation. (C) 2013 Elsevier B.V. All rights reserved.