带-NH2的嘧啶环对钌配合物与DNA相互作用的瞬态发光特性的影响

采用时间分辨的发光光谱技术,分别测量了两种新合成的钌配合物[Ru(bpy)2 (dpbpd(NH2)2)]2 和[Ru(phen)2(dpbpd(NH2)2)]2 与小牛胸腺脱氧核糖核酸(ctDNA)相互作用时的瞬态发光动力学过程,并与以往对[Ru(phen)2dppz]2 等的研究结果进行对比,从而研究带-NH2的嘧啶环对配合物与DNA作用动力学过程的影响.结果表明:这两种含有带-NH2的嘧啶环的钌配合物与DNA相互作用时的发光按双指数规律衰减,发光寿命为几十纳秒,比dppz类钌配合物与DNA作用时的发光衰变寿命(几百纳秒)小一个数量级.归因于嘧啶环上的N和-NH2可能与水分子、DNA的碱基对或磷酸骨架形成氢键,从而加快激发态的无辐射弛豫,削弱发射光强,缩短发光寿命.该结论为进一步研究配合物分子与DNA的相互作用的机理提供了一定的依据.

Effects of Pyrimidine Ring with-NH2 on Transient Luminescence Properties in Ruthenium Complexes Bonding to DNA

To study the effects of the pyrimidine ring with -NH2 on transient luminescence properties in ruthenium complexes bonding to DNA, transient luminescence dynamics process of two ruthenium complexes [Ru(bpy)2(dpbpd(NH2)2)]2+ and [Ru(phen)2(dpbpd(NH2)2)]2+bonding to calf thymus DNA(ctDNA) have been studied by using time-resolved spectroscopy, and the results are compared with results in previous researches. Two complexes both show biexponential decay in emission on bonding to DNA, and the luminescence lifetime is within tens of nanoseconds, about ten times shorter than the luminescence lifetime (several hundreds nanoseconds) of dppz-kind ruthenium complexes. It is attributed to that the hydrogen-bonds may form between N or -NH2 of pyrimidine ring and water molecule, base pairs or phosphoric skeleton. The hydrogen-bonds can quicken the nonradiative decay of the excitated state, weaken the luminescence intensity, and shorten the luminescence lifetime. The conclusion offers an argument to study the interaction mechanism for the complex bonding to DNA.