Synthesis, DNA and Photocleavage Studies of Ru(II) Polypyridyl Complexes: [Ru(dppz)(pyz)₄](ClO₄)₂ and [Ru(dppz)(dmpyz)₄](ClO₄)₂ Complexes

Abstract

In view of the growing interest for the synthesis of metal complexes and their interaction with DNA, we have synthesized and characterized two complexes containing ruthenium as metal center. The complexes are of the type [Ru(dppz)L 4 ](ClO 4 ) 2 where L are biologically important ligands such as pyrazole and dimethylpyrazole. The characterization of these complexes is done by 1 H NMR, 13 C NMR, elemental analysis and mass spectroscopy. The interaction of these complexes with CT DNA was monitored and binding constants were determined using absorption and fluorescence spectroscopy. The mode of binding was found to be intercalative for both complexes and was determined using hydrodynamic viscosity studies. The complexes were further studied for photocleavage studies with supercoiled plasmid pBR322 DNA.

Tunable DNA cleavage activity promoted by copper(ii) ternary complexes with N-donor heterocyclic ligands

“…Several metal complexes, mainly containing Cu(II) or Ru(II), exhibit photo-induced DNA cleavage. 2,3,[8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] Recently, an oxidative artificial chemical nuclease -[Cu(1,10-phenanthroline) 2 (H 2 O)] 2+ -was reported as an agent for protein engineering, where the complex ion was used as a substitute for the enzyme DNase I for the generation of random mutagenesis libraries. 25 Also, the precise mechanism of metal complexes activity towards DNA was investigated using a complementary approach where the fate of the metal ion coupled to the artificial nuclease was followed by fluorescence, in addition to agarose gel electrophoresis, to observe the substrate DNA.…”

“…The relatively low activity of complex 1 led us to try photostimulation to enhance its DNA cleavage ability, as observed with other metal complexes. 2,3,[8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] DNA photocleavage promoted by 1-4 was examined following the conversion of supercoiled plasmid DNA (F I) to the open circular (F II), and linear DNA (F III) forms using agarose gel electrophoresis. The cleavage reactions were carried out as earlier described 8,30 (see the ESI †).…”