Two novel polypyridyl{PylP=2-(pyren-1-yl)-lH-imidazo[4,5-f][1,10]phenanthroline,bpy=2,2′-bipyridine,dmb=4,4′-dimethyl-2,2′-bipyridine}ruthenium(Ⅱ)complexes[Ru(bpy)_(2)(PyIP)]^(2+)(1)and[Ru(dmb)_(2)(PyIP)]^(2+)(2)have been synthesized and characterized by elemental analysis,ES-MS and a H NMR spectroscopy.The DNA-binding of these complexes were investigated by spectroscopic methods and viscosity measurements.The experimental results indicate that both complexes 1 and 2 bind to calf thymus DNA in classical intercalation mode,and however,complex 1 intercalated more strongly than complex 2,due to the different ancillary ligands.
TAN Li-fengXIAO YueZHU Wei-guoZHOU Yuan-qingZHANG Sheng
The luminescence dynamics of a polypyridyl ruthenium II [Ru（phen）2（ip）]2＋ and 5,10,15,20- tetraphenylporphyrin （H2TPP） dyad have been measured by using time-resolved fluorescence spectroscopy. The transient luminescent spectra of the dyad show an ultrafast energy transfer within 300 ps after pho- toexcitation of the [Ru（phen）2（ip）]2＋ at 453 am. However, no energy transfer has been observed as the excitation wavelength is 400 nm, corresponding to the absorption peak of H2TPP. The origin of the energy transfer from [Ru（phen）2（ip）]2＋ to H2TPP has been analyzed according to the FSrster energy-transfer theory.
The transient luminescence of three kinds of ruthenium complexes [Ru(bpy)2(7-CH3-dppz)]2+, [Ru(bpy)2(7-F-dppz)]2+ and [Ru(phen)2(7-F-dppz)]2+ bound to calf thy-mus DNA (ctDNA) has been studied by using the time-resolved spectroscopy. The results show that the luminescence is due to the radiative decay from the charge-transfer states to the ground state. By the interaction with DNA, the radia-tiveless rate of the photoexcited Ru complex molecules decreases, which results in the increase of luminescence lifetime and efficiency. The structure of the Ru com-plex has an important impact on the interaction with DNA. The [Ru(bpy)2(7-CH3-dppz)]2+ shows the longest luminescence lifetime (about 382 ns), while the [Ru(bpy)2(7-F-dppz)]2+ shows the shortest lifetime (about 65 ns). The possible origin of the luminescence dynamics is discussed.
