推拉式二苯乙烯衍生物的光异构化反应机理的研究

发布时间：2018-05-03 07:00

本文选题：4-(N + N-二甲基氨基)-4　；参考：《西北大学》2017年硕士论文

【摘要】：本文主要应用态平均完全活性空间自洽场方法对三种典型的推拉式二苯乙烯衍生物进行研究。主要包括两个部分:第一部分对推拉式二苯乙烯衍生物作了详细的介绍以及对三种典型的代表物质DNS、ANS以及NS的研究历史进行了总结。第二部分应用态平均完全活性空间自洽场方法优化得到系间交叉点和圆锥交叉点,并且基于此对比研究DNS、ANS以及NS的光异构化反应机理。第一章简述了推拉式二苯乙烯衍生物的性质、应用和研究背景。第二章介绍了对DNS光异构化反应机理的研究,用CASSCF方法优化DNS在光异构化反应路径中的圆锥交叉点和系间交叉点。结果表明DNS的trans→cis光异构化反应由单线态和三线态两种路径参与完成,而且这两种路径的过程中都有N,N-二甲基氨基、碳碳双键以及硝基的扭转运动参与。第三章详细介绍了对ANS光异构化反应机理的研究,所用方法与第二章相同,通过与DNS对比发现,ANS与其有相似的反应机理,但是唯一区别是无法优化得到反式构型处S1和T1间的系间交叉点。说明供电子基强度的变化对单线态路径的影响小于对三线态路径的影响,取代基的供电子性越强则S1和T1间的系间窜跃越强。第四章研究了 NS的光异构化反应机理。计算得到的其与DNS和ANS具有相似的反应机理,但是在顺式或反式构型区域处均未优化的到S1态和T1态之间的系间交叉点。进一步说明了供电子基的存在对于NS的单线态光反应机理影响不大,但是对三线态路径影响很大,也再次说明了供电子基取代有加强三线态路径的反应几率的作用。
[Abstract]:In this paper, three typical push-pull stilbene derivatives are studied by using the state mean complete active space self-consistent field method. It mainly includes two parts: the first part introduces the push-pull stilbene derivatives in detail and summarizes the research history of three typical representative substances DNSANS and NS. In the second part, the intersystem crossing points and conical cross points are optimized by using the state-average completely active space self-consistent field method. Based on this, the photoisomerization mechanism of DNSANS and NS is studied. In the first chapter, the properties, applications and research background of push-pull stilbene derivatives are briefly introduced. In chapter 2, the mechanism of photoisomerization of DNS is studied. The CASSCF method is used to optimize the conical cross point and intersystem crossing point of DNS in the photoisomerization reaction path. The results show that the photoisomerization of trans cis in DNS is accomplished by two paths, one is the single state and the other is the triplet state, and both of these paths are involved in the torsional motion of N- N-dimethyl amino, carbon-carbon double bond and nitro. In chapter 3, the mechanism of photoisomerization of ANS is introduced in detail. The method is the same as that in chapter 2. By comparing with DNS, it is found that the reaction mechanism of ans is similar to that of DNS. But the only difference is that there is no way to optimize the intersection point between S1 and T1. It is shown that the change of the intensity of the donor group has less effect on the single state path than on the three-wire state path. The stronger the electron supply of the substituent is, the stronger the intersystem transition between S1 and T1 is. In chapter 4, the photoisomerization mechanism of NS was studied. The calculated reaction mechanism is similar to that of DNS and ANS, but there is no optimal intersystem point between S1 state and T1 state in the cis or trans configuration region. It is further explained that the existence of electron donor group has little influence on the photoreaction mechanism of NS singlet state, but it has a great influence on the three-wire state path, and it also explains again the effect of the electron donor group on the probability of strengthening the three-wire state path.
【学位授予单位】：西北大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O625.12

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