Binding and photocleavage of DNA by mixed ligand Co(III) and Ni(II) complexes of thiophene[2, 3-b] quinoline and phenanthrolie/bipyridine

Abstract

In order to systematically perform an experimental and theoretical study on DNA binding and photocleavage properties of transition metal complexes of the type [M(L)2(L1)](PF6)n x xH2O (where M = Co(III) or Ni(II), L = 1,10-phenanthroline or 2.2' bipryidine, L1 = Thiophene [2,3-b] quinoline (qt), n = 3 or 2 and x = 5 or 2) have been synthesized and characterized by elemental analysis, IR, 1H NMR, UV and magnetic susceptibility data. The DNA-binding properties of these complexes have been investigated with UV-Vis, viscosity measurements, thermal denaturation and cyclic voltametric studies. It is experimentally found that all the complexes are bound to DNA via intercalation in the order [Co(bpy)2(qt)](PF6)3 > [Co(phen)2(qt)](PF6)3 > [Ni(phen)2(qt)](PF6)2 > [Ni(bpy)2(qt)](PF6)2. The photocleavage studies with pUC19 DNA shows that all these complexes promoted the conversion of SC form to NC form in absence of 'inhibitors'.

Synthesis, characterization and DNA binding of copper(II) complexes with mixed ligands of 1, 10-phenanthroline / 2-2’ bipyridyl, L-methionine and ethylamine: Studies on antimicrobial and anti-cancer activities

“…When CT-DNA is added to a solution of complexes, marked decrease in the peak current and potential values were observed. The cyclic voltammetric behavior was not affected by the addition of very large excess of DNA, indicating that the decrease of peak current of complexes after the addition of DNA due to the binding of complex to the DNA [31] . When concentration of DNA increased, the changes in peak current and potential become slow.…”

DNA binding and cleavage by dinuclear nickel(II) complexes with neutral bidentate ligands and ciprofloxacin

“…spectrophotometer (Shimadzu) at room temperature and reflectance spectra were recorded on Lamda 19 UV/VIS/NIR spectrophotometer with 1.0000-nm data interval. Ni(II) complexes were found to be paramagnetic with a l eff value ranging between 2.8 and 3.4 ± 0.20 BM as expected for typical d 8 octahedral systems (Figgis, 1986;Prabahkara and Bhojya Naik, 2008). For octahedral nickel(II) complexes, the crystal field theory allows for three spin allowed d-d transitions, namely 3 A 2g (F) ?…”

Synthesis, characterization DNA binding and biological activity of Copper(II) complexes with mixed ligands

“…When CT-DNA is added to a solution of complexes, marked decrease in the peak current and potential values were observed. The cyclic voltammetric behavior was not affected by the addition of very large excess of DNA, indicating that the decrease of peak current of complexes after the addition of DNA due to the binding of complex to the DNA 38 . When concentration of DNA increased, the changes in peak current and potential become slow.…”