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
The interaction of ruthenium polypyridyl complex with DNA has been studied by isothermal titration calorimetry (ITC). The results show that complex [Ru(phen)2PMIP]2+ {phen=1,10-phenanthroline, PMIP=2-(4-methylphenyl)i...The interaction of ruthenium polypyridyl complex with DNA has been studied by isothermal titration calorimetry (ITC). The results show that complex [Ru(phen)2PMIP]2+ {phen=1,10-phenanthroline, PMIP=2-(4-methylphenyl)imidazo1,10-phenanthroline} interacts with calf thymus DNA (CT DNA) in terms of a model for a single set of identical sites through intercalation. The results are in agreement with our previous observations from spectroscopic methods and viscosity measurements. In addition, the results further show that the driving force for DNA binding with the complex is mainly driven by the enthalpy changes, and the contribution from the entropy changes to this driving force is negligible.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
The formation of heterobimetallic ruthenium?complex was investigated by absorption and emission spectra. As an intercalator of DNA, the luminescent monometallic ruthenium?complex [Ru(bpy)2tpphz]2+could coordinate with...The formation of heterobimetallic ruthenium?complex was investigated by absorption and emission spectra. As an intercalator of DNA, the luminescent monometallic ruthenium?complex [Ru(bpy)2tpphz]2+could coordinate with Zn2+to form the nonluminescent heterobimetallic complex [Ru(bpy)2(tpphz)Zn]4+. The emission intensity of complex decreased as increasing the amounts of Zn2+and the luminescence was almost lost at the ratio of / of 1. After binding to DNA, the peripheral coordination site on the tpphz ligand remained accessible for Zn2+, the coordination occurred from the oppsite side of helix with respect to intercalated [Ru(bpy)2tpphz]2+and the nonluminescent heterobimetallic complex was formed. On the other hand, the [Ru(bpy)2(tpphz)Zn]4+also bound to DNA by intercalation and situated the region of the intercalated [Ru(bpy)2tpphz]2+between the base pairs of DNA. The complex looked like a molecular nut (the Zn2+) and bolt (the [Ru(bpy)2tpphz]2+).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The interaction of ruthenium polypyridyl complex with DNA has been studied by isothermal titration calorimetry (ITC). The results show that complex [Ru(phen)2PMIP]2+ {phen=1,10-phenanthroline, PMIP=2-(4-methylphenyl)imidazo1,10-phenanthroline} interacts with calf thymus DNA (CT DNA) in terms of a model for a single set of identical sites through intercalation. The results are in agreement with our previous observations from spectroscopic methods and viscosity measurements. In addition, the results further show that the driving force for DNA binding with the complex is mainly driven by the enthalpy changes, and the contribution from the entropy changes to this driving force is negligible.
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The formation of heterobimetallic ruthenium?complex was investigated by absorption and emission spectra. As an intercalator of DNA, the luminescent monometallic ruthenium?complex [Ru(bpy)2tpphz]2+could coordinate with Zn2+to form the nonluminescent heterobimetallic complex [Ru(bpy)2(tpphz)Zn]4+. The emission intensity of complex decreased as increasing the amounts of Zn2+and the luminescence was almost lost at the ratio of / of 1. After binding to DNA, the peripheral coordination site on the tpphz ligand remained accessible for Zn2+, the coordination occurred from the oppsite side of helix with respect to intercalated [Ru(bpy)2tpphz]2+and the nonluminescent heterobimetallic complex was formed. On the other hand, the [Ru(bpy)2(tpphz)Zn]4+also bound to DNA by intercalation and situated the region of the intercalated [Ru(bpy)2tpphz]2+between the base pairs of DNA. The complex looked like a molecular nut (the Zn2+) and bolt (the [Ru(bpy)2tpphz]2+).
