Two polypyridyl ligands DCHIP (2 hydro 3,5 dichlorophenyl imidazo phenanthroline),MDHIP(2,4 dihydrophenyl imidazophenanthroline) and their ruthenium?complexes [Ru(phen)2 MDHIP]2+and [Ru(phen)2DCHIP]2+were prepared. Th...Two polypyridyl ligands DCHIP (2 hydro 3,5 dichlorophenyl imidazo phenanthroline),MDHIP(2,4 dihydrophenyl imidazophenanthroline) and their ruthenium?complexes [Ru(phen)2 MDHIP]2+and [Ru(phen)2DCHIP]2+were prepared. Their DNA binding properties were studied by spectroscopic methods and viscosity measurements. The results indicated that the complexes both bound to DNA by partial intercalation mode, but [Ru(phen)2DCHIP]2+exhibited stronger binding affinity for DNA than [Ru(phen)2 MDHIP]2+due to the different planarities and steric effects of ligands. On the other hand, after binding to DNA, the fluorescence intensity of [Ru(phen)2MDHIP]2+decreased, while the fluorescence intensity of [Ru(phen)2 DCHIP]2+increased.展开更多
Two structurally related polypyridyl ligands ODHIP(3,4-dihydroxyl-imidazophenanthroline), MDHIP(2,4-dihydroxyl-imidazo phenanthroline) and their ruthenium(II) complexes [Ru(phen) 2ODHIP] 2+ and [Ru(phen) 2MDHIP] 2+ we...Two structurally related polypyridyl ligands ODHIP(3,4-dihydroxyl-imidazophenanthroline), MDHIP(2,4-dihydroxyl-imidazo phenanthroline) and their ruthenium(II) complexes [Ru(phen) 2ODHIP] 2+ and [Ru(phen) 2MDHIP] 2+ were prepared and characterized. Their DNA-binding properties were studied by spectroscopic methods and viscosity measurements. The results indicated that the two complexes are bound to DNA by different modes due to the different planarities of ligands. For the complex [Ru(phen) 2MDHIP] 2+, the 2- position ortho group of MDHIP could form an intramolecular hydrogen bond with the nitrogen atom of the imidazole ring to extend the planarity and strengthen the binding affinity. On the other hand, the 4- position ortho group hindered the complex from intercalating into the base pairs of DNA, and finally, making the complex bind to DNA by a partial intercalative mode. However, for the complex [Ru(phen) 2ODHIP] 2+, there was no intramolecular hydrogen bond formed and the two ortho groups further increased the steric effect and decreased the binding affinity, thus making the complex bind to DNA by groove binding mode.展开更多
Two enantiomerically pure polypyridyl ruthenium(Ⅱ) complexes Δ- and Λ-[Ru(bpy) 2HPIP](PF 6) 2{HPIP=2-(2-hydroxyphenyl)imidazo[4,5-f][1,10]phenanthroline} were synthesized and characterized. DNA-binding studies indi...Two enantiomerically pure polypyridyl ruthenium(Ⅱ) complexes Δ- and Λ-[Ru(bpy) 2HPIP](PF 6) 2{HPIP=2-(2-hydroxyphenyl)imidazo[4,5-f][1,10]phenanthroline} were synthesized and characterized. DNA-binding studies indicated that both enantiomers bound to calf thymus DNA by intercalation, the Δ- enantiomer exhibited a stronger binding affinity than the Λ- enantiomer. Upon irradiation at 302 nm, both enantiomers were found to promote cleavage of plasmid pBR 322 DNA from the supercoiled form Ⅰ to the open circular form Ⅱ, but the Δ-enantiomer exhibited a higher cleaving efficiency for DNA due to the different binding affinities to DNA. The cleaving mechanisms for Δ- and Λ-[Ru(bpy) 2HPIP] 2+ were identical, the hydroxyl radical(OH ·) was likely to be the reactive specie responsible for the cleavage of plasmid pBR 322, and the photoreduction of Ru(Ⅱ) complex with concomitant hydroxide oxidation was the important step in the DNA cleavage reaction.展开更多
文摘Two polypyridyl ligands DCHIP (2 hydro 3,5 dichlorophenyl imidazo phenanthroline),MDHIP(2,4 dihydrophenyl imidazophenanthroline) and their ruthenium?complexes [Ru(phen)2 MDHIP]2+and [Ru(phen)2DCHIP]2+were prepared. Their DNA binding properties were studied by spectroscopic methods and viscosity measurements. The results indicated that the complexes both bound to DNA by partial intercalation mode, but [Ru(phen)2DCHIP]2+exhibited stronger binding affinity for DNA than [Ru(phen)2 MDHIP]2+due to the different planarities and steric effects of ligands. On the other hand, after binding to DNA, the fluorescence intensity of [Ru(phen)2MDHIP]2+decreased, while the fluorescence intensity of [Ru(phen)2 DCHIP]2+increased.
文摘Two structurally related polypyridyl ligands ODHIP(3,4-dihydroxyl-imidazophenanthroline), MDHIP(2,4-dihydroxyl-imidazo phenanthroline) and their ruthenium(II) complexes [Ru(phen) 2ODHIP] 2+ and [Ru(phen) 2MDHIP] 2+ were prepared and characterized. Their DNA-binding properties were studied by spectroscopic methods and viscosity measurements. The results indicated that the two complexes are bound to DNA by different modes due to the different planarities of ligands. For the complex [Ru(phen) 2MDHIP] 2+, the 2- position ortho group of MDHIP could form an intramolecular hydrogen bond with the nitrogen atom of the imidazole ring to extend the planarity and strengthen the binding affinity. On the other hand, the 4- position ortho group hindered the complex from intercalating into the base pairs of DNA, and finally, making the complex bind to DNA by a partial intercalative mode. However, for the complex [Ru(phen) 2ODHIP] 2+, there was no intramolecular hydrogen bond formed and the two ortho groups further increased the steric effect and decreased the binding affinity, thus making the complex bind to DNA by groove binding mode.
文摘Two enantiomerically pure polypyridyl ruthenium(Ⅱ) complexes Δ- and Λ-[Ru(bpy) 2HPIP](PF 6) 2{HPIP=2-(2-hydroxyphenyl)imidazo[4,5-f][1,10]phenanthroline} were synthesized and characterized. DNA-binding studies indicated that both enantiomers bound to calf thymus DNA by intercalation, the Δ- enantiomer exhibited a stronger binding affinity than the Λ- enantiomer. Upon irradiation at 302 nm, both enantiomers were found to promote cleavage of plasmid pBR 322 DNA from the supercoiled form Ⅰ to the open circular form Ⅱ, but the Δ-enantiomer exhibited a higher cleaving efficiency for DNA due to the different binding affinities to DNA. The cleaving mechanisms for Δ- and Λ-[Ru(bpy) 2HPIP] 2+ were identical, the hydroxyl radical(OH ·) was likely to be the reactive specie responsible for the cleavage of plasmid pBR 322, and the photoreduction of Ru(Ⅱ) complex with concomitant hydroxide oxidation was the important step in the DNA cleavage reaction.
