四苯基乙烯衍生物双光子吸收特性的理论研究

发布时间：2018-03-20 03:04

本文选题：双光子吸收　切入点：二聚效应　出处：《山东师范大学》2017年硕士论文　论文类型：学位论文

【摘要】：具有强双光子吸收性质的有机分子材料,在诸多领域具有较大的应用潜能,例如3维光信息存储,光动力疗法和双光子荧光显微镜(TPEM)等。尤其TPEM在活细胞组织中的应用,更是获得了广泛的关注。因此,探索有机双光子吸收材料的潜能与应用,成为了科研工作者研究的热潮。但是,在实验材料、器材、费用等因素的限制下,在实验上探寻材料性能的速度与效率并不尽如人意。近年来,通过量子化学计算理论研究双光子吸收材料结构与性能的关系,成为了诸多科研者的工作重点。理论研究可以指导实验分子的合成,从而大大节省了科研的时间与费用。目前,一系列具有π共轭中心、电子给体(D)和受体(A)的对称或不对称的电荷转移分子(如D-π-D,D-π-A,D-A-D等)在理论和实验上被广泛研究。各种分子内结构因素(如分子平面性,给体和受体的强度,π共轭中心的电子特性等)和分子间相互作用(如聚集效应和溶剂效应)对双光子吸收性质的影响有了充分地研究。因此,根据已有的分子结构与性质关系,理论设计性能优良的双光子吸收材料成为了可能。本文在杂化密度泛函水平上,理论研究了一系列由四苯基乙烯基团构建的有机分子体系,并讨论了体系的结构与性质的关系。主要工作可分为以下二个部分:第一部分研究了一类四苯基乙烯衍生物双光子吸收性质的二聚效应和同分异构效应;第二部分是基于四苯基乙烯衍生物,理论设计了一系列有机双光子吸收分子结构,并计算了设计分子的双光子吸收性质。一、四苯基乙烯衍生物双光子吸收性质的二集效应和同分异构效应计算了一类新型四苯基乙烯衍生物ENPOMe分子及其同分异构体的双光子吸收性质。考虑了4种分子单体结构,统计了分子内各苯环平面间的二面角,计算了各单体结构的双光子吸收截面。计算结果显示,分子异构对双光子吸收性质有重要影响,分子局部的平面性能够增强分子的双光子吸收强度。为了探索聚集效应,设计了12种共价键相连接的二聚体结构,并计算了它们的双光子吸收性质。研究发现,分枝的线性排列能够有效增强材料的双光子吸收性质。由于分枝与主干之间夹角相似的结构具有类似的分子内共轭通道和电荷转移能力,所以分子的双光子吸收性质也类似。此外,分子局部的平面性和整体的线性可能是实验上观测到的聚集诱导双光子吸收增强的原因。二、基于四苯基乙烯衍生物双光子吸收材料的分子设计在实验分子的基础上,综合利用已有的双光子吸收分子结构与性质之间的关系,理论设计了一系列有利于增强双光子吸收截面的分子结构。通过改变分子中电子给体基团,增强给体的强度,设计了2种分子结构,相应的双光子吸收强度均比实验分子有所增强。同时,还发现,当改变咔唑基与分子主体的连接方式时,可以显著提高双光子吸收强度。通过参考已有的实验结果,设计了不同共轭桥连接的3种二聚体结构,结果显示,采用乙烯和乙炔共轭桥连接的二聚体结构与实验分子的二聚体结构相比,在长波范围内,双光子吸收有较大增强。因此,计算结果证实了我们的设计思路。理论设计的分子不仅具有较强的双光子吸收,而且,由于分子均含有螺旋桨结构的四苯基乙烯基团,所以同时具有聚集诱导发光特性,可以成为优良的双光子荧光探针分子。
[Abstract]:With the organic molecular material with strong two-photon absorption properties, has great potential in many fields, such as 3 dimensional optical information storage, photodynamic therapy and two-photon fluorescence microscopy (TPEM). Especially TPEM in living tissues, it is widely concerned. Therefore, to explore the potential and application organic two photon absorption materials, has become a scientific research boom. However, in the experimental equipment, materials, costs and other factors limit, in the experiment to explore the speed and efficiency of material performance is not satisfactory. In recent years, the relationship through quantum chemical calculation theory of two-photon absorption material structure and performance, become many researchers focus on theoretical research. Synthetic molecules can guide the experiment, which saves the time and cost of scientific research. At present, a series of conjugated center electron donor (D) and Receptor (A) charge symmetric or asymmetric transfer molecules (such as D- -D D- -A PI, PI, D-A-D) in theory and experiment have been widely studied. The various factors in the molecular structure (such as molecular plane, donor and acceptor strength, conjugated center of electronic properties etc.) and intermolecular phase the interaction (such as aggregation effect and solvent effect) has been fully research on two-photon absorption properties. Therefore, according to the relationship between the molecular structure and properties, the theory of the design of excellent properties of two-photon absorption materials as possible. Based on the hybrid density functional theory research level, a series of four phenyl ethylene organic molecular systems group construction, and discusses the relationship between the structure and properties of the system. The main work can be divided into the following two parts: the first part is to study a class of four phenyl ethylene derivatives of two photon absorption properties of two poly effect and isomeric effect The second part is; four phenyl ethylene derivatives based on the theory, design a series of molecular structure of organic two-photon absorption, two-photon absorption properties and molecular design calculation. A two-photon, four phenyl ethylene derivatives of two-photon absorption properties of two in effect and the isomeric effect on a new class of four phenyl ethylene derivatives ENPOMe molecules and their isomers. Considering the absorption properties of 4 kinds of molecular monomer structure, the statistics of the dihedral angle between the benzene ring plane molecular two-photon, each monomer structure to calculate the absorption cross section is calculated. The results show that the molecular heterogeneity has an important effect on the two-photon absorption properties of planar molecules to local enhanced two photon absorption intensity. In order to explore the molecular aggregation effect, design two dimeric structure 12 covalently connected, their two-photon absorption properties were calculated. The results show that points Branch of the linear array can effectively enhance the two-photon absorption properties of materials. The structures are similar to the angle between the branch and the trunk has a similar intramolecular conjugated charge transfer and channel capacity, so the two-photon absorption properties of molecules are similar. In addition, the local molecular planarity and overall linear may be experimentally observed aggregation two photon induced absorption enhancement. Two, four phenyl ethylene derivatives of two photon absorption materials based on the molecular design of molecules based on the comprehensive utilization of the two-photon absorption molecular structure and properties of the theory, design a series is conducive to enhancing the two-photon absorption cross section by changing the molecular structure of electronic. The donor groups in the molecule, to enhance the strength, design 2 kinds of molecular structure, the corresponding two-photon absorption intensity than the experimental molecular improved. At the same time, also Found that when the connection mode change of carbazole and molecular entities, can significantly improve the two-photon absorption intensity. The experimental results with reference to the existing design, different conjugated bridge connecting 3 two dimer structure, results showed that the ethylene and acetylene conjugated bridge connecting two dimeric structure and experimental molecular poly two body structure than in the long wavelength range, two-photon absorption has greatly enhanced. Therefore, the calculated results proved that our design ideas. The molecular theory has not only design and better two-photon absorption, because, four phenyl vinyl group containing molecular structure of the propeller, so at the same time with aggregation induced emission, can become double photon fluorescent probe molecule excellent.

【学位授予单位】：山东师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O625.12

【参考文献】