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Synthesis, Characterization, DNA Binding Properties, Fluorescence Studies and Toxic Activity of Cobalt(III) and Ruthenium(II) Polypyridyl Complexes


The new ligand 4-(isopropylbenzaldehyde)imidazo[4,5-f ][1,10]phenanthroline (ippip) and its complexes [Ru(phen)2(ippip)]2+(1),[Co(phen)2(ippip)]3+(2),[Ru(bpy)2(ippip)]2+(3),[Co(bpy)2(ippip)]3+(4)(bpy=2,2-bipyridine) and (phen=1,10-phenanthroline) were synthesized and characterized by ES+-MS, 1H and 13C NMR. The DNA binding properties of the four complexes were investigated by different spectrophotometric methods and viscosity measurements. The results suggest that complexes bind to calf thymus DNA (CT-DNA) through intercalation. When irradiated at 365 nm, the complexes promote the photocleavage of pBR322 DNA, and complex 1 cleaves DNA more effectively than 2, 3, 4 complexes under comparable experimental conditions. Furthermore, photocleavage studies reveal that singlet oxygen (1O2) plays a significant role in the photocleavage.

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We are grateful to G. Bhanuprakash reddy, Scientist-G, National Institute of Nutrition, Hyderabad for helping to record CD spectra and also grateful to DST New Delhi for financial support.

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Correspondence to Sirasani Satyanarayana.

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Nagababu, P., Shilpa, M., Latha, J.N.L. et al. Synthesis, Characterization, DNA Binding Properties, Fluorescence Studies and Toxic Activity of Cobalt(III) and Ruthenium(II) Polypyridyl Complexes. J Fluoresc 21, 563–572 (2011).

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  • Cobalt(III) and ruthenium(II) mixed-ligands
  • DNA-binding
  • Fluorescence studies
  • Photocleavage of plasmid DNA
  • Toxic studies