一种钌配合物与DNA相互作用发光增强的超快过程研究

采用时间分辩激光光谱技术,研究了一种钌配合物Ru(dmb)2(mitatp)]2 发光增强的超快过程。采用比较方法测量了Ru(dmb)2(mitatp)]2 和Ru(dmb)2(mitatp)]2 /DNA复合物的瞬态发光弛豫过程。Ru(dmb)2(mitatp)]2 和Ru(dmb)2(mitatp)]2 /DNA复合物的发光均来源于Ru(dmb)2(mitatp)]2 中的电荷转移单态和三重态到基态的辐射跃迁。通过钌配合物与DNA的相互作用,Ru(dmb)2(mitatp)]2 的荧光寿命由339 ns延长至589 ns;磷光寿命由16μs延长至21μs,总的发光强度增强了约1个数量级。分析表明,Ru(dmb)2(mitatp)]2 发光寿命和发光强度的增加可能来源于Ru(dmb)2(mitatp)]2 与DNA之间的电荷转移态的形成,它导致Ru(dmb)2(mitatp)]2 的最低激发单态和三重态到基态的无辐射概率的减小,增强了Ru(dmb)2(mitatp)]2 发光效率。

Study on Ultrafast Dynamics of Luminescence Enhancement in a [DNA and Ru] Complex

The ultrafast dynamics of the luminescence enhancement in Ru(dmb)2(mitatp)]2+ and Ru(dmb)2(mitatp)]2+/DNA complex has been studied by use of time-resolved luminescence spectroscopy. The transient luminescence relaxation processes of Ru(dmb)2(mitatp)]2+ and Ru(dmb)2(mitatp)]2+/DNA complex have been measured with comparison method. The luminescence is due to the transition between charge transfer singlet and triplet states. The results show that after interaction with DNA, the lifetimes of fluorescence and phosphorescence of Ru(dmb)2(mitatp)]2+ complex are prolonged from 339 ns to 589 ns and from 16 μs respectively, and the total luminescence intensity is enhanced by one order of magnitude. The possible origin may be the formation of the new energy levels of the photoexcited charge-transfer singlet and triplet states by the interaction between Ru(dmb)2(mitatp)]2+ and DNA resulting in the decrease of the nonradiative decay rate from the lowest excited state to the ground state and the increase of the luminescence efficiency.