理论设计俘精酸酐和二芳基乙烯类光致异构化分子开关

发布时间：2019-05-22 02:04

【摘要】：近年来,随着科技水平的飞速发展以及科学家们对光化学领域的不断深入探索,有机光致变色化合物已经迅速成为活跃的研究领域。其中,常见的有机光致异构化分子包括俘精酸酐类、二芳基乙烯类、偶氮苯类以及螺吡喃类等。俘精酸酐和二芳基乙烯作为典型的光致异构化分子,由于它们具有良好的抗疲劳性、热力学稳定性以及快速响应等特点,在分子开关、光学信息存储等领域有着广阔的应用和发展前景。它们主要存在两种异构体,即开环体和闭环体,在适当的吸收波长照射下,这两种异构体之间可以发生相互转化。基于这种结构特性的考虑,它们经常作为分子开关的重要组成单元。因此,有机光致变色化合物这一课题的研究具有十分重要的理论价值和实际意义。本论文主要采用了密度泛函理论(DFT)和含时密度泛函理论(TDDFT)方法讨论了俘精酸酐和二芳基乙烯类衍生物的基态几何结构以及低激发态的电子结构性质。其中,俘精酸酐类衍生物的研究主要集中在吸收性质的讨论以及多功能分子开关的设计,二芳基乙烯类衍生物的研究主要集中在非线性光学性质的讨论上。主要内容总结如下:1.理论研究不同取代基对呋喃取代的俘精酸酐光谱性质的影响以及一系列新型的呋喃取代的俘精酰亚胺二聚体的分子设计由于呋喃取代的俘精酸酐(闭环体和开环体)具有较短的吸收波长从而限制了它们的实际应用,尤其是在许多半导体器件中。因此,我们通过密度泛函理论方法讨论了不同取代基对呋喃取代的俘精酸酐的几何结构和光谱学性质的影响。我们发现,在R3位置,氨基(NH2)的引入使呋喃取代的俘精酸酐的闭环体表现出明显的波长红移,且它的闭环体与开环体之间呈现出较大的波长差值。因此,这一分子有希望成为多功能分子开关的候选者。在这个工作的基础上,我们通过不同的呋喃取代的俘精酰亚胺单体的组合进一步设计了九种bis-furylfulgimide二聚体(BFF:1-9),并且讨论了它们吸收光谱的分离情况。其中,反对称的BFF-6二聚体展示出最大的光致异构化潜能。所以,我们从理论的角度上详细地讨论了它的光致异构化机理。2.理论研究一系列B(C6F5)2配位的二噻吩基乙烯衍生物的二阶非线性光学性质在本文中,我们计算了一系列实验合成的B(C6F5)2配位的二噻吩基乙烯衍生物的静态一级超极化率(βtot),我们发现,2-B(C6F5)2分子表现出较好的非线性光学响应。在此分子的基础上,我们引进了一个简单的N=N-ph配体,并且考虑了取代基的供电子和吸电子能力对它们非线性光学行为的影响。计算结果显示,配体的引入显著地提高了分子的非线性光学性质,而且,随着取代基供电子和吸电子能力的增强,开环体和闭环体的βtot值都得到了显著地提高。其中,闭环体的βtot值高于对应的开环体,这是由于闭环的过程中形成了更大的π共轭结构。此外,在我们设计的五组分子中,闭环体5c展示出最大的βtot值(7361.4×10-30 esu),它是对应开环体5o的29.8倍。此外,我们采用含时密度泛函理论方法分析了它们的吸收光谱以及前线分子轨道性质。最后,我们在ω=0.000-0.065 a.u.的频率范围内讨论了色散效应对其动态一级超极化率(βtot(ω))的影响。我们希望当前的理论工作能够为以后的理论或实验的非线性光学材料设计提供帮助。
[Abstract]:In recent years, with the rapid development of science and technology and the deep exploration of the field of photochemistry, the organic photochromic compounds have rapidly become active research fields. Among them, the most common organic photo-isomerizing molecules include, for example, the alicyclic type, the diarylethylene group, the azobenzene group, and the snail-like type, and the like. As a typical photoisomerization molecule, the fine acid and the diaryl ethylene have wide application and development prospect in the fields of molecular switches, optical information storage, and the like because of the characteristics of good fatigue resistance, thermodynamic stability and rapid response. They mainly have two isomers, namely an open-loop body and a closed-loop body, which can be mutually transformed between the two isomers under the irradiation of an appropriate absorption wavelength. Based on this structural characteristics, they are often used as an important component of the molecular switch. Therefore, the study of the organic photochromic compound has very important theoretical and practical significance. In this paper, the ground state geometry and the properties of the low-excited state are discussed in this paper by using the density functional theory (DFT) and the time-time density functional theory (TDDFT) method. In this paper, the research of the derivatives of the diarylvinyl derivatives is mainly focused on the discussion of the absorption property and the design of the multi-functional molecular switch, and the research of the diaryl ethylene derivatives is mainly focused on the discussion of the nonlinear optical properties. The main contents are as follows:1. The effect of the different substituents on the spectral properties of the captives and the molecular design of a series of novel trimer-substituted captive protamine dimers has been studied by the theoretical study of the molecular design of a series of novel and substituted captives (closed-loop and open-loop) with a short absorption wavelength to limit their real-time. Inter-application, especially in many semiconductor devices. Therefore, we have discussed the influence of different substituents on the geometric and spectroscopic properties of the captives substituted by the different substituents by means of the density functional theory. It was found that in the R3 position, the introduction of amino (NH2) gave a clear wavelength red shift on the closed-loop body surface of the captured acid solution, and its closed-loop body and the open-loop body exhibited a large wavelength difference. Thus, this molecule has the desire to be a candidate for a multi-function molecular switch. On the basis of this work we further designed nine bis-furylfurbiide dimers (BFF:1-9) and discussed the separation of their absorption spectra. Among them, the antisymmetric BFF-6 dimer shows the greatest photoisomerization potential. Therefore, we have discussed its photoisomerization mechanism in detail from the theoretical point of view. In this paper, the second order nonlinear optical properties of a series of B (C6F5)2-coordinated diatomic ethylene derivatives have been studied in this paper. We have calculated the static first hyperpolarizability of a series of experimentally synthesized B (C6F5)2-coordinated diatomic-based ethylene derivatives, we found that, 2-B (C6F5)2 molecules show good nonlinear optical response. On the basis of this molecule, we introduced a simple N = N-ph ligand and considered the effect of the substituents on the nonlinear optical behavior of the electron and electron-absorbing capacity of the substituent. The results show that the introduction of the ligands significantly improves the non-linear optical properties of the molecules, and, with the increase of the electron and electron-absorption capacity of the substituents, the ttot values of the open-loop body and the closed-loop body are significantly improved. In which the ttot value of the closed-loop body is higher than the corresponding open-loop body, which is due to the formation of a larger ring resonator structure in the closed-loop process. In addition, in the five-group molecule that we design, the closed-loop body 5c exhibits the largest Bot value (7361.4-10-30 esu), which is 29.8 times the corresponding open-loop body 5o. In addition, we used the time-density functional theory to analyze their absorption spectra and the properties of the front-line molecular orbital. Finally, we have discussed the effect of the dispersion effect on the dynamic first-order hyperpolarizability (Bot) in the range of the frequency range of 0 = 0.000-0.065 a. u. We hope that the current theoretical work can help the design of nonlinear optical materials for later theory or experiment.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O621.22

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