Effects of substituent on the DNA-binding of ruthenium(II) complexes containing asymmetric tridentate intercalative ligands

Abstract

Three novel unsymmetric tridentate ligands, namely, ptmi (ptmi = 3-(1,10-phenanthroline-2-yl)-as-triazino[5,6-f]-5-methoxyisatin), pti (pti = 3-(1,10-phenanthroline-2-yl)-as-triazino-[5,6-f]isatin), ptni (ptni = 3-(1,10-phenanthroline-2-yl)-as-triazino[5,6-f]-5-nitroisatin), and their complexes [Ru(tpy)(ptmi)](ClO 4 ) 2 (tpy = 2,2 0 :6 0 ,2 00 -terpyridine) (1), [Ru(tpy)(pti)](ClO 4 ) 2 (2), and [Ru(tpy)(ptni)](ClO 4 ) 2 (3) were prepared and characterized by elemental analysis, 1 H NMR, ES-MS. The electrochemical behaviors were studied by cyclic voltammetry. The DNA-binding properties of these complexes were investigated by the spectroscopic method, viscosity measurements, and thermal denaturation. Theoretical studies on these complexes were also performed with the density functional theory (DFT) method. The experimental results showed that these complexes bind to calf thymus (CT-DNA) in an intercalative mode. The order of DNA-binding affinities (A) of these complexes is A(1) \ A(2) \ A(3). The trend in the DNA-binding affinities of this series of complexes can be reasonably explained by the DFT calculations.

Application of d6 transition metal complexes in fluorescence cell imaging

“…In addition to tri-diimine Ru species, some complexes containing asymmetric tridentate ligands were found to be suitable as DNA intercalators. 104 Liu and co-workers proposed [Ru(tpy)(pti)] 2+ derivatives (tpy = 2,2 0 :6 0 , 2 00 -terpyridine; pti = 3-(1,10phenanthroline-2-yl)-as-triazino[5,6-f]isatin) as DNA intercalators showing a higher DNA affinity in concordance with the withdrawing ability of the substituent in the intercalative ligand (Fig. 32).…”

Antimicrobial and nuclease activity of mixed polypyridyl ruthenium(II) complexes

“…The temperature at which 50% of the DNA has become single strand is known as melting temperature. It can be determined from the thermal denaturation curves of DNA by monitoring the absorption changes at 260 nm [24]. The T m observed for DNA (100 μM) is 74.2 ± 0.2°C under our experimental conditions (Fig.…”

Synthesis, characterization and DNA binding and cleavage properties of ruthenium(II) complexes with various polypyridyls

“…[1][2][3] Ruthenium(II) complexes bind to DNA in a non-covalent interaction fashion, such as electrostatic binding for cation, groove binding for large ligands, intercalative binding for planar ligands and partial intercalative binding for incomplete planar ligands. [4][5][6] Several ruthenium complexes were found to be potent anticancer substances with remarkable activity and lower toxicity than platinum complexes. 7 In co-ordination chemistry, terpyridines are of special interest due to their ability to form stable complexes with many transition metal ions.…”