几种特殊分子内质子转移体系的激发态动力学行为及光物理性质研究

发布时间：2018-11-17 06:34

【摘要】：基于所选取的几种新型分子内质子转移体系,我们使用密度泛函理论和含时密度泛函理论分别优化得出其基态和激发态的稳定构型,通过特征官能团的红外振动谱、前线分子轨道、吸收光谱和荧光光谱等一系列光物理参数,结合体系中氢键的变化情况,分析了所产生的光谱频移、激发态电荷重新分布等光物理现象,并尝试阐释了激发态分子内质子转移的详细过程和相关机理。第一章中,主要介绍了体系光激发和衰变的相关过程,氢键的性质及其作用,并阐述了氢键作用在分子体系可能产生的光物理和光化学变化。第二章介绍了几种研究多电子体系的量子力学理论方法,并介绍了密度泛函理论和含时密度泛函理论的基本内容。第三章主要研究了靛蓝分子及其衍生物在基态和激发态的主要性质变化,发现分子内的两个分子内氢键在光激发后具有相反的变化趋势,氢键加强和减弱同时发生。并且在R4R4’位置的卤素取代使得分子的吸收光谱峰值发生显著的红移,并且卤素取代能显著加强衍生物的电荷迁移速率。第四章主要研究了1,3-二(2-吡啶亚胺基)-4,7-二羟基异吲哚分子激发态分子内双质子转移机理。通过固定一系列羟基长度对分子进行柔性扫描,绘制出分子的三维势能变化图,直观地展示激发态质子转移过程。第五章主要关注了1,8-二羟基苯并[a,c]吩嗪中π共轭结构对分子内质子转移影响,发现分子内π共轭结构的增多能明显加大分子光谱的斯托克斯位移并有助于质子转移的发生。第六章主要研究了锚定基组修饰的新型蓝色荧光蛋白分子,发现丙二酸和丙二腈取代基可以使该蓝色荧光蛋白发生荧光淬灭现象,猜测可能是由于该取代基参与分子激发态电荷重新分布,并充当重要的供电子基团。
[Abstract]:Based on the selected new intramolecular proton transfer systems, we use density functional theory (DFT) and time-dependent density functional theory (DFT) to optimize the stable configuration of ground state and excited state, respectively. A series of photophysical parameters, such as frontier molecular orbitals, absorption spectra and fluorescence spectra, are analyzed in combination with the changes of hydrogen bonds in the system, and the photophysical phenomena such as spectral frequency shift and charge redistribution of excited states are analyzed. The detailed process and related mechanism of intramolecular proton transfer in excited states are also attempted to be explained. In chapter 1, the related processes of photoexcitation and decay, the properties and functions of hydrogen bonds are introduced, and the possible photophysical and photochemical changes of hydrogen bonds in molecular systems are discussed. In the second chapter, several quantum mechanical methods for studying multi-electron systems are introduced, and the basic contents of density functional theory and time-dependent density functional theory are also introduced. In chapter 3, the main properties of indigo molecule and its derivatives in ground state and excited state are studied. It is found that the two intramolecular hydrogen bonds have the opposite trend after photoexcitation, and the strengthening and weakening of hydrogen bond occur simultaneously. In addition, the peak absorption spectra of the molecules shifted significantly due to the substitution of halogen at the R4R4'position, and the charge transfer rate of the derivatives was significantly enhanced by the substitution of halogens. In chapter 4, the mechanism of intramolecular double proton transfer in the excited state of 1H _ 3- bis (2-pyridyllidene) -4N _ 7- dihydroxyisoindole is studied. Through the flexible scanning of the molecule with a fixed series of hydroxyl lengths, the three-dimensional potential energy change diagram of the molecule is drawn, and the excited state proton transfer process is displayed intuitively. In chapter 5, the effect of 蟺 conjugated structure on intramolecular proton transfer in 1-dihydroxy benzo [azac] phenazine is studied. It is found that the increase of intramolecular 蟺 conjugated structure can increase the Stokes shift of molecular spectrum and contribute to the occurrence of proton transfer. In chapter 6, a novel blue fluorescent protein modified by anchored group was studied. It was found that malonic acid and malonitrile substituted group could cause fluorescence quenching of the blue fluorescent protein. It is assumed that the substituent may be involved in the redistribution of the excited charge of the molecule and act as an important electron donor group.
【学位授予单位】：河南师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O561

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