飞秒瞬态光谱测量和相干控制研究新型光敏剂咔咯能量转移和电荷转移过程

The incidence of cancer has increased in recent years. Photodynamic therapy (PDT) is a treatment that uses a drug, called a photosensitizer and a particular type of light. When photosensitizers are exposed to a specific wavelength of light, they produce a form of oxygen that kills nearby cells. Corrole and its derivatives were found to function both for tumor detection and intervention with safety and targeting advantages over standard chemotherapeutic agents. Therefore it is very important to investigate its photophysical and photochemical characters and select candidates for anticarcinogens. We will investigate the influence of periphecal groups and center mental on the ultrafast vibrational relaxation process，quantum yield of intersystem crossing and singlet oxygen. The electron transfer process between the water-soluble corroles and DNA will also be studied. In addition, we will use a femtosecond laser source with adaptive pulse shaping together with a molecular feedback in a learning loop to search for and synthesize such 'smart' laser pulses. Our control objective is to enhance the triplet yield of a model photosensitizer water-soluble corrole, which then leads to enhancement of the overall PDT process. We will also use the same method to control the process of electron transfer between water-soluble corrole and DNA.

近年来我国癌症发病率不断上升，光动力学疗法(Photodynamic Therapy,PDT)作为一种新型治疗方法备受关注。由于咔咯及其衍生物优良的靶组织选择性，体内代谢快、PDT活性高，使其有望成为新一代具有分子识别能力的"智能型"光敏剂，因此合成和研究新型光敏剂成为非常重要的研究方向。 本项目拟用超快光谱技术研究新型光敏剂咔咯（corrole）的光物理和光化学特性，进行用于光动力治疗药物的筛选。研究咔咯超快振动弛豫、系间窜越几率和单线态氧几率与周边取代基和中心金属的关系；以及水溶性镓咔咯与DNA复合物之间的超快电荷转移过程，用量子相干调控控制咔咯系间窜越和单线态氧产率，以及水溶性镓咔咯与DNA复合物之间的超快电荷转移过程。

在本项目中，我们用瞬态光谱法研究了两个系列自由corrole的光物理特性，我们发现meso位氟取代引发的内转换加快以及系间窜越的提高，发现meso位碘取代也可以加快系间窜越速率。另外，我们搭建了量子相干调控系统，并用该系统,通过自学算法，优化激发光脉冲形状，提高了光激发后金属镓咔咯的三重态量子产率约20%，并测得其的动力学过程，进一步还进行了复杂脉冲的测量。经过分析，我们认为金属镓的热态参与了调控，调控后的脉冲使热态增加了一个去往三重态的弛豫通路。为物理手段控制化学反应路径进行了有益的探索。