• New mixed ligand complexes of ruthenium(II) that incorporate a modified phenanthroline ligand: Synthesis, spectral characterization and DNA binding

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      https://www.ias.ac.in/article/fulltext/jcsc/114/04/0403-0415

    • Keywords

       

      Ruthenium(II) complexes; modified phenanthroline ligand; spectroscopy; DNA binding; fluorescence enhancement

    • Abstract

       

      The hexafluorophosphate and chloride salts of two ruthenium(II) complexes, viz. [Ru(phen)(ptzo)2]2 and [Ru(ptzo)3]2+, where ptzo = 1,10-phenanthrolino[5,6-e]1,2,4-triazine-3-one (ptzo) — a new modified phenanthroline (phen) ligand, have been synthesised. These complexes have been characterised by infrared, UV-Vis, steady-state emission and1H NMR spectroscopic methods. Results of absorption and fluorescence titration as well as thermal denaturation studies reveal that both thebis- and tris-complexes of ptzo show moderately strong affinity for binding with calf thymus (CT) DNA with the binding constants being close to 105M-1 in each case. An intercalative mode of DNA binding has been suggested for both the complexes. Emission studies carried out in non-aqueous solvents and in aqueous media without DNA reveal that both [Ru(phen)(ptzo)2]2+ and [Ru(ptzo)3]2+ are weakly luminescent under these solution conditions. Successive addition of CT DNA to buffered aqueous solutions containing [Ru(phen)(ptzo)2]2+results in an enhancement of the emission. These results have been discussed in the light of the dependence of the structure-specific deactivation processes of the MLCT state of the metallo-intercalator with the characteristic features of its DNA interaction. In doing so, attempts have been made to compare and contrast its properties with those of the analogous phenanthroline-based complexes including the ones reported by us previously.

    • Author Affiliations

       

      S Murali1 C V Sastri1 Bhaskar G Maiya1

      1. School of Chemistry, University of Hyderabad, Hyderabad - 500 046, India
    • Dates

       
  • Journal of Chemical Sciences | News

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