水溶性苝系衍生物荧光探针识别金属离子的光物理机制计算研究

随着人们对荧光化合物电子光谱和光物理行为的深入研究，在利用荧光分子作为探针，检测各种不同体系的状态及其变化等方面都有了巨大的进展。其中，N，N′-二天冬氨酸铵盐-3，4，9，10-四羧酸二酰亚胺(PTCDA)是一种水体环境中选择性好灵敏度高的典型荧光分子探针。本文用密度泛函理论对PTCDA的光物理机制进行研究。计算了PTCDA分子在理想状态下的最优构型，电荷布居和激发光谱。根据计算结果，拟合此苝系衍生物激发态与Cu2+结合前后的吸收光谱，与Cu2+结合前后，吸收光谱峰形相似，加铜后整体吸收峰位发生了红移，有猝灭变色现象。通过与实验值的对比，计算所得分子构型合理有效，激发光谱谱峰位置切合实际。分析得出：PTCDA分子对二价铜离子有较好荧光探测活性，其光信号响应机制属于分子内电荷转移(ICT)机制。当分子接收二价铜离子时，吸收光谱谱峰位置红移，分子内电荷转移方向和强度均发生变化，既有猝灭信号，也有光的颜色变化信号，是一种具有猝灭与变色双信号的荧光探针材料，具有很大的开发潜力。所做工作只是用量子化学计算方法在分子荧光探针领域进行光物理响应机制分析的初步探索，可以为该领域提供系统而有价值的理论参考。

Derivative Fluorescence Probe Recognition Results of the Light Physical Mechanism of Metal Ions

As people deeply study the electronic spectra of fluorescent compounds and photophysical behavior, enormous progress has been made in the aspect of changes and states of different systems in the use of fluorescent molecules as probes. PTCDA is a kind of typical fluorescent molecular probe that is highly sensitive and selective in water environment. This paper makes a research on the physical mechanism of light of PTCDA by TDF (Density Functional Theory), calculates the optimal configuration the charge population and excitation spectra of PTCDA molecules under ideal condition and acquires PTCDA fluorescence emission spectra then analyses that PTCDA is a kind of quenching and dual colorimetric signal probe response. Its optical signal response mechanism belongs to ICT( Intramolecular Charge Transfer) mechanism. According to the results, this perylene derivatives is fitted with Cu2+ excited state absorption spectra. Before and after the combination with Cu2+, the peak shape of absorption spectrum is similar. When copper is added, the overall absorption peak position occurred redshift, quenching discoloration happens. By comparing with experimental values, the calculated molecular configuration is reasonable and effective and the peak of excitation spectra is realistic. Analysis shows that: PTCDA molecules divalent copper ions have better fluorescence detection activity, the optical signal response mechanisms are intramolecular charge transfer (ICT) mechanisms. When a molecule receives divalent copper ions, the absorption spectrum peak position redshifts, intramolecular charge transfer direction and intensity changes. There occur both quenching signal and discoloration signal. It is a kind of fluorescent probe material with double quenching and discoloration fluorescent signal, which has great potential for development. This paper makes an early-stage exploration of the physical mechanism of light response mechanism analysis in molecular fluorescent probe field and can be a systematically valuable theoretical reference for this field.