荧光素类探针分子发光机理的研究

项目名称： 荧光素类探针分子发光机理的研究

项目编号： No.21203187

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 物理化学

项目作者： 周潘旺

作者单位： 中国科学院大连化学物理研究所

项目金额： 25万元

中文摘要： 荧光素自1871年首次被合成以来，便由于其良好的性能而被广泛用于标记和检测生物分子。长期以来，人们以荧光素为底物，设计并合成出了大量的荧光素类衍生物，但是，对荧光素类衍生物发光机理的研究则比较少。目前人们普遍认为，淬灭荧光素类衍生物荧光的主要途径是光诱导的电子转移（PET）。最近，我们利用TDDFT和RICC2方法对PET机理进行了检验，结果发现，对荧光素类衍生物而言，发生PET之后所形成的电荷转移态的能量明显高于发光态，无法淬灭荧光，这与PET机理相矛盾。理论计算与实验预测相矛盾的事实促使我们需要对荧光素类衍生物分子的发光机理展开进一步研究。本项目拟利用超快时间分辨光谱与激发态量子化学相结合的方式，对荧光素类衍生物的发光机理开展研究，期望从实验上找出淬灭荧光素类衍生物荧光的主要途径，并从理论上阐明分子结构对荧光素类衍生物荧光量子产率的影响。

中文关键词： 荧光素；内转换；光致电子转移；发光机理；

英文摘要： Since fluorescein was synthesized for the first time in 1871, it has been used widely for labeling and sensing biomolecules.For a long period of time, a large number of fluorescein-based fluorescence probes have been developed, however, studies on the luminescence mechanism of fluorescein derivatives have been seldom been reported. Nowdays it is generally accepted that photo-induced electron transfer is the major pathway for quenching the fluorescence of the fluorescein derivatives. Recently, we used the TDDFT and RICC2 to check the validity of the PET mechanism, the calculated results indicated that the energy of the charge transfer state is clearly higher than that of the bright state, which can not be used to quench fluorescence, this is in contrast with the PET mechanism. Thus, further studies are needed to investigate the luminescence mechanism of fluorescein derivatives. This project will use the ultrafast time-resolved spectroscopy and quantum chemistry calculations to study the luminescence machanism of fluorescein derivatives, the objectives of this project are to find the major pathway for quenching the fluorescence of the fluorescein derivatives from experimental studies, and to illustrate the effect of molecular stuctrue on the fluorescence quantum yield of fluorescein derivatives using the theoretic

英文关键词： fluorescein；internal conversion；photo-induced electron transfer；luminescence mechanism；