Mixed-ligand complexes of ruthenium(II) incorporating a diazo ligand: Synthesis, characterization and DNA binding

Abstract

Mixed-ligand complexes of the type [Ru(N-N) 2 (dzdf)]Cl 2 , where N-N is 2,2′-bipyridine (bpy), 1,10-phenanthroline (phen) and 9-diazo-4,5-diazafluorene (dzdf), have been synthesized and characterized by elemental analysis, UV-Vis, IR and NMR spectroscopy. Binding of these complexes with calf thymus DNA (CT-DNA) has been investigated by absorption spectroscopy, steady-state emission spectroscopy and viscosity measurements. The experimental results indicate that the size and shape of the intercalating ligands have marked effect on the binding affinity of the complexes to CT-DNA. The complex [Ru(phen) 2 (dzdf)]Cl 2 binds with CT-DNA through an intercalative binding mode, while the complex [Ru(bpy) 2 (dzdf)]Cl 2 binds electrostatically.

New homodi-and heterotrinuclear metal complexes of Schiff base compartmental ligand: interaction studies of copper complexes with calf thymus DNA

“…In the plot of I 0 /I versus [Cu]/[DNA], K is given by the ratio of the slope to the intercept. The K values for complex 5 and complex 1 estimated using (3) are 0.45 and 0.10, respectively, [49] suggesting that complex 5 interacts with CT-DNA more strongly in comparison to complex 1 which is consistent with the absorption studies results. …”

“…The quenching extent of fluorescence of EB bound to DNA is utilized to determine the extent of binding of complexes and DNA [48]. Binding of the complex results in the displacement of bound EB molecule with the reduction of emission intensity due to fluorescence quenching of free EB by water [49]. The emission spectra of EB bound to DNA in presence and absence of complex 1 and 5 are given in Fig.…”

Chiral and Achiral Macrocyclic Copper(II) Complexes: Synthesis, Characterization, and Comparative Binding Studies with Calf-Thymus DNA

“…The quenching extent of fluorescence of EB bound to DNA is used to determine the binding of the complex and DNA. Binding of the complex results in the displacement of bound EB molecules with a reduction of emission intensity due to fluorescence quenching of free EB by H 2 O [45]. The emission spectra of EB-bound DNA in the absence and presence of complex 1 and 3 are given in Fig.…”

Synthesis, Characterization, and Photophysical Studies of Some Novel Ruthenium(II) Polypyridine Complexes Derived from Benzothiazolyl hydrazones

“…In the 1 H NMR spectra of the all complexes, the NH protons, aromatic protons, and the protons of methyl group of ligands are shifted downfield due to coordination to the metal ions [5,12,26,27]. Two multiplet signals of eight protons observed in the spectrum of the complexes 4a-4d at 7.58 ppm and 8.31 ppm were assigned to bipyridyl protons, and the signals at 7.35-7.58 ppm and 7.80 ppm in the spectrum of complexes 5a, 5d, and 5e were assigned to phen protons [20,21,28]. Thus, all the protons were found to be in their expected region.…”

“…The other absorption bands of the ligands are due to various - * and - * transitions [5,14,27,29]. In the UV-vis absorption spectra of complexes and the bands at 322, 332, and 323 nm should receive a dominant contribution from transition involving the ligands 3a, 3d, 3e, respectively [6,14,28]. In particular, the bands with 290-300 nm range should receive a dominant contribution from - * transition involving bpy and phen moieties [7,[31][32][33].…”