【作者】 薛林；

【导师】 李希友；

【作者基本信息】 山东大学 ， 无机化学， 2012， 博士

【摘要】 π-π共轭体系的自组装在有机电子器件方面的潜在应用,在过去的几年里吸引了人们广泛的关注。许多功能型的π体系分子,例如：苝二酰亚胺(Perylene tetracarboxylic acid diimide,简称PDI),卟啉,酞菁等化合物已经被广泛地研究,以期望它们能在有机半导体材料、太阳能转化、激光染料、液晶以及生物荧光探针,太阳能电池等方面有良好的应用前景。最近几年,研究工作者们把重点转向在溶液,有机凝胶以及柱状液晶相中利用π-π聚集自组装成一维的纳米结构,利用这些有序的结构来做成功能型材料。为了满足PDI化合物在不同领域的应用,通过对其结构进行化学修饰,达到控制苝二酰亚胺类化合物性质的目的,是获得具有新型光电性质的PDI新材料的重要手段之一。本文就这种苝二酰亚胺类化合物的结构和性能之间的关系进行研究,通过在PDI化合物中引入不同的功能性基团,从而得到一些具有特殊性质的苝二酰亚胺化合物并对其性质进行深入的研究。以下是本论文的主要内容：第一章：概述了PDI及其衍生物的发展历史以及研究背景、合成方法、基本性质,重点介绍了超分子聚集体的研究进展。第二章：通过在酰亚胺的一端连接上不同数目取代的疏水的烷基链,合成了三种PDI的衍生物。采用电子吸收光谱和荧光光谱对这一系列化合物在溶液中的聚集行为进行了研究。结果表明,在PDI分子一端的疏水烷基链的数目越多,分子的聚集越明显,但是在这些PDI的芳香环之间却没有明显地基态相互作用。利用电子吸收和发射光谱以及红外和X射线衍射实验对这些化合物在固态下的聚集行为也进行了研究。结果表明,随着PDI分子一端烷基链数目的增加,聚集的方式由H形转变为J形,固态下聚集的形貌由弯曲的小带状转变为长而有序的线状。由此可以得出,我们可以通过改变烷基链的数目来达到控制分子聚集的方式,有序性以及形貌的目的。这将有助于我们设计新型有机聚集体的分子。第三章：合成了两个共价键连接的分别含有两个(二聚体1)或六个(六聚体2)PDI单元的PDI衍生物。用电子吸收和荧光发射光谱对这两种化合物在溶液中的聚集性质进行了表征。实验结果表明,即使在很稀的溶液里面,六聚体2也是倾向于通过分子间的作用力来形成更大的分子间聚集体。但是二聚体1通过分子内的聚集使这两个PDI单元通过面对面的堆积形成折叠的构象。红外光谱表明,在二聚体1和六聚体2的分子聚集体中,酰胺氮和羰基氧能形成氢键。二聚体1的干凝胶的形貌表现出具有很大长宽比的束状纤维。但是六聚体2只是表现出来小的棒状聚集。出现这样的差别主要是控制着分子聚集的不同作用力之间相互干扰所导致的。由此可以得出,我们通过调节分子之间超分子作用力的相互干扰,可以达到控制分子聚集的形貌和尺寸的目的。第四章：将N-(2-氨乙基)-3,4,5-三(十二烷基)苯甲酰胺连接在花二酰亚胺的一端,然后将这个不对称的PDI衍生物通过乙二胺和均苯三甲酰氯相连形成了PDI的三聚体。测试了这个化合物在多种有机溶剂中的凝胶形成能力。对三聚体的凝胶性质通过电子吸收和荧光发射光谱进行了表征。结果表明三聚体的凝胶状态形成了典型的H聚集。稀释凝胶的紫外-可见吸收和荧光光谱随着温度的升高基本上没有什么变化,这些表明凝胶中存在稳定的分子间的聚集。通过对干凝胶X射线衍射实验以及原子粒显微镜(AFM)对形貌的观察。我们发现三聚体的凝胶具有纳米带状结构。这对于我们在以后的设计合成分子中,如何选择功能型的基团来得到有序结构的聚集体的工作具有指导意义。更多还原

【Abstract】 Self-assembled π-conjugated systems have attracted tremendous attention in the past years owing to their potential application in organic electronics. Numerous functional π systems molecules, for example, perylenetetracarboxylic diimide (PDI), porphyrins, phthalocyanines and so on have been intensively investigated aiming to their application as organic photoconductors, semiconductors, solar energy conversion, liquid crystal materials, biological fluorescent probes and solar cells and so on.In recent years, emphasis has been given on the organization of tailored functional π systems by self-assembly leading to one-dimensional stacks of π-π aggregates in solution, in organogels, and in columnar liquid crystalline (LC) phases. Driven by the demands of diverse applications, the modification on molecular structure of PDI aimed at changing the photophysical properties is one of the most active fields of PDI studies. How to find a structure with novel properties has always been a problem in this area. In this paper, in order to find the relationship between structure and properties of PDIs, we introduced some functional groups to the PDI compounds, endowed these molecules with some special functions and studied their influence on the properties. The content of this thesis includes:Chapter1, the synthesis, properties and applications of perylenetetracarboxylic diimide derivatives have been reviewed. The research progress of supramolecular aggregates based on Perylenetetracarboxylic Diimides is selected as the focus of this research.Chapter2, three perylenetetracarboxylic diimide (PDI) derivatives comprising a different number of hydrophobic alkoxy chains at one imide nitrogen were synthesized. The aggregation behavior of this series of compounds was investigated by UV-vis absorption and emission spectra. The results indicated that large number of hydrophobic alkyl chains at one end of the PDI molecules can induce significant aggregation in solution, but without obvious ground state interaction between the PDI aromatic cores. The aggregation behavior of this series of compounds in solid state was studied by absorption and IR spectra as well as X-ray diffraction (XRD) experiments. The morphology of the solid aggregates was investigated by scanning electronic microscopy (SEM). With an increase of the number of alkyl chains at one end of these PDI molecules, the aggregation mode varies from H type to J type, while the morphology of the solid aggregates changes from small bending belts to long ordered wires. This research demonstrated that one can control the aggregation mode, the order, and the morphology of the molecular aggregates by changing the number of alkyl chains. This information can be useful in the design of novel organic materials which exhibit molecular aggregation.Chapter3, two new perylenetetracarboxylic diimide (PDI) derivatives, namely dimer1and hexamer2composed of two or six PDI units respectively, are prepared. The aggregation behaviours of these two compounds in solution were investigated by the absorption and fluorescence spectra. The results indicate that hexamer2intend to form large molecular aggregates via intermolecular process even in a much diluted solution. But dimer1prefers to take a folded conformation with the two PDI units stacking in a face-to-face way via an intramolecular process. Infrared spectra revealed the presence of hydrogen bonding between the amide nitrogen and carbonyl oxygen in the molecular aggregates of dimer1and hexamer2. The morphology of the dried gel of dimer1shows bundle of long fibres with very large aspect ratio. But hexamer2presents only small rod-like aggregates with small aspect ratio. This difference is likely caused by the disturbance among different driving forces for the molecular aggregation.Chapter4, a new perylene tetracarboxylic diimide (PDI) trimer1composed of three PDI subunits, which linked at one end with3,4,5-tris(dodecyloxy)benzamide groups has been designed and prepared. The gelating abilities of the trimer in different solvents have been investigated and the results indicated that trimer1can form gel in apolar solvent, such as methyl cyclohexane (MCH). The property of the gel of this trimer has been investigated by UV-vis absorption and emission spectra. The results indicate that the gel of trimer1is composed of typical H aggregates. Temperature-dependent absorption spectra and fluorescence spectra of the diluted gel show that there are almost no changes with the temperature increasing, indicates that the molecular self-assembly in gel is very stable. The structure of dried gel has been investigated by X-ray diffraction (XRD) experiment and the morphology has been measured by atomic force microscopy (AFM). This research revealed that the gel of the trimer formed ordered nano fiber-like structure. This information may be useful for the design of novel organogels based on perylene tetracarboxylic diimides.更多还原