湾位官能化双亲性POSS-PDI纳米杂化材料的合成及其自组装行为的研究

发布时间：2018-01-07 06:26

本文关键词：湾位官能化双亲性POSS-PDI纳米杂化材料的合成及其自组装行为的研究　出处：《东华大学》2015年硕士论文　论文类型：学位论文

更多相关文章：湾位 功能化 POSS 傒酰亚胺 自组装

【摘要】：傒酰亚胺（Perylene dimide，PDI）是具有优异稳定性和强烈光物理特性的稠环芳烃，因具有极强的π-π相互作用，能够自发的形成有序堆积体，是独特的分子电学材料，在太阳能电池，生物荧光探针，化学感应器等诸多领域的研究中受到广泛的关注。其分子结构及其固体材料的凝聚态结构是决定PDI类材料光物理性质及其应用性能的关键，其中通过亲疏水作用调控PDI的凝聚态结构是研究热点和重点之一。笼形倍半硅氧烷POSS是具有丰富烷基链、直径（约0.78nm）的疏水性无机纳米粒子，可作为大取代基改善PDI的溶解性和限制π-π堆砌；三乙二醇（TEG）是含有亲水性基团的线性结构物质，且末端羟基可与溶剂形成氢键或可作为进一步改性的官能团。将纳米颗粒POSS和TEG同时引入PDI分子中，在上述多重因素影响下，PDI的自组装行为会如何？为此本文合成了侧基均为POSS而湾位分别为H（未取代）、Br和三乙二醇（TEG）的三种POSS-PDI-POSS分子：POSS-PDIH-POSS、POSS-PDIBr-POSS、POSS-PDITEG-POSS，研究了PDI分子的溶液自组装行为、自组装产物的凝聚态结构和晶态下光物理性质，以期考察和理解在多重相互作用下PDI分子的溶液自组装。主要研究成果如下： 1.以（PTCDA）为原料，通过先湾位溴代后侧基POSS取代的方法合成POSS-PDIBr-POSS，使用柱层析分离得到湾位1,6和1,7取代POSS-PDIBr-POSS产物（同一Rf值），然后再通过重复长晶体的方法得到了湾位1,7取代POSS-PDIBr-POSS的晶体。以湾位1,7取代POSS-PDIBr-POSS为原料，在K2CO3和十八冠六醚的催化体系催化下合成了湾位三乙二醇取代的POSS-PDITEG-POSS，使用层析柱和长晶体得到纯净的湾位1,7取代的POSS-PDITEG-POSS。通过FTIR、NMR和MALDI-TOF等表征明晰了化合物的结构和高纯度，为后续自组装行为的研究打下了基础。 2.紫外-可见吸收光光谱和荧光光谱是表征PDI分子溶液自组装行为的通用手段，其测试结果的准确性、可靠性和易获取性，在很大程度上依赖于分子结构和溶剂的种类。为此本研究首先系统考察了溶剂的种类、溶液浓度、复合溶剂组成对POSS-PDI-POSS自组装行为的影响，并据此建立了一套适用于PDI快速定位溶剂、浓度等关键因素的方法，，包括样品处理、溶剂性评估、选取溶剂、滴定实验等，为探索三种分子溶液自组装行为奠定基础。进而比较分析了上述三种POSS-PDI-POSS分子的溶液自组装行为。结果表明在稀溶液的单分子态下，POSS-PDITEG-POSS的0-0电子跃迁吸收峰（567nm）相比于POSS-PDIH-POSS, POSS-PDIBr-POSS（524nm，522nm）吸收红移，而它们的荧光发射依次为589nm，543nm和550nm，说明湾位溴代和三乙二醇的取代造成傒平面扭曲，破坏了π-π相互作用，这点也可在分子模拟构型优化和能级差计算辅助中所验证。三个分子在己醇中均可发生自组装，其临界浓度分别为1.24E-6M、1.8E-4M和4.8E-4M，对POSS-PDIH-POSS, POSS-PDIBr-POSS而言，丙醇/二氧六环是理想的复合溶剂体系，而POSS-PDITEG-POSS的理想溶剂体系则为THF/水。在溶液自组装中，三个分子均具有吸收宽化和ε0-0/ε0-1比值减小且形成二聚体的特点，但是聚集体在荧光表现上可知，只有POSS-PDIH-POSS具有发射，后两者均发生显著淬灭，说明它们形成的二聚体在构型上可能具有区别。 3.这三个分子通过相分离方法可以形成特定形貌的聚集体，荧光、偏光显微镜和SEM、TEM等手段表征表明，POSS-PDIH-POSS和POSS-PDIBr-POSS形成针状晶体，在晶体中两种分子均以二聚体为最小基元形成不连续堆砌，POSS-PDIH-POSS呈J型二聚体，POSS-PDIBr-POSS由于极大的长轴位移以至在萘环之间形成H型二聚体，这可能是POSS-PDIBr-POSS晶体具有独特光物理性质的原因：相较于POSS-PDIH-POSS荧光发射光谱蓝移和荧光量子产率低的特点，其蓝移现象也区别于湾位溴代、侧基为线性链的PDI的红移。而POSS-PDITEG-POSS则形成由片状聚集体堆砌成的球状颗粒，高分辨率TEM下可观察到片状聚集体由间距为2.7nm较深色线状条带（纳米颗粒POSS）组装成的有序体。通过变温FTIR和亚稳态有序结构的形成分析，以及POSS-PDI-POSS以二聚体为基元堆砌的特点，推测其形成机理为：分子形成二聚体后首先堆砌成层，然后层层堆砌，最后由于亲疏水和氢键等共同作用形成球状晶体。
[Abstract]:Xi imide (Perylene dimide PDI) is a polycyclic aromatic hydrocarbon with excellent stability and strong photophysical properties, because of its strong pi pi interactions, can spontaneously form ordered accumulation, is unique in the molecular electrical materials, solar cells, biological fluorescent probes have attracted the attention of research on chemical sensors and many other fields. Its molecular structure and solid material condensed structure is the key material of PDI optical properties and application properties of the hydrophilic hydrophobic interaction, through the regulation of PDI condensed structure is a research hotspot and focus.
Silsesquioxanes POSS has rich alkyl chain, the diameter (about 0.78nm) hydrophobic inorganic nanoparticles can be used as a substitute for improving the solubility of PDI and limit tt-tt stacking; triethylene glycol (TEG) is a linear structure material containing hydrophilic groups, and terminal hydroxyl groups can form hydrogen bonds with the solvent or as a further modification of the functional groups. The nano particles of POSS and TEG at the same time, the introduction of PDI molecules, under the influence of these multiple factors, PDI self-assembly behavior will be how? This paper synthesized side groups were POSS and H respectively for the Bay (unsubstituted), Br and triethylene glycol (TEG) three POSS-PDI-POSS: POSS-PDIH-POSS, POSS-PDIBr-POSS, POSS-PDITEG-POSS molecules, the self-assembly behavior of the solution PDI molecular research, self condensed state structure and photophysical properties of crystal assembled products, in order to investigate and understand the interaction in multiple PDI molecules Self - assembly of solution. The main research results are as follows:
In 1. (PTCDA) as raw materials, through the first bay of bromo substituted side based POSS synthesis of POSS-PDIBr-POSS, using column chromatography by 1,6 and 1,7 bay to replace the POSS-PDIBr-POSS product (same Rf value), and then through the method of repeated long crystal has been 1,7 to replace the POSS-PDIBr-POSS Bay Bay in a crystal. 1,7 replaced POSS-PDIBr-POSS as raw material, the bay of triethylene glycol substituted POSS-PDITEG-POSS synthesis catalyzed by K2CO3 in the six and eighteen crown ether, using chromatography column and long crystal pure Bay 1,7 substituted POSS-PDITEG-POSS. through FTIR, NMR and MALDI-TOF were used to characterize the structures of these compounds were clear and high purity, for subsequent research the self-assembly behavior of the foundation.
2. UV Vis absorption spectroscopy and fluorescence spectroscopy is a common means of self-assembly of molecular characterization of PDI solution, the test result accuracy, reliability and accessibility, species depend on the molecular structure and solvent. This study first investigates the type of solvent, concentration, solvent effect of POSS-PDI-POSS composition on the self-assembly behavior, and established a set of suitable for PDI rapid positioning method of key factors such as solvent, concentration, solvent including sample treatment, assessment, selection of solvent, titration experiments, in order to explore the molecular self-assembly behavior of three kinds of solution to lay the foundation. Then it compares the self assembling behavior of the solution the above three kinds of POSS-PDI-POSS molecules. The results show that in single molecule in dilute solution, 0-0 electronic transition of POSS-PDITEG-POSS absorption peak (567nm) compared to POSS-PDIH-POSS, POSS-PDIBr-POS S (524nm, 522nm) absorption redshift, and their fluorescence emission were 589nm, 543nm and 550nm, indicating to replace the Bay - Bromination and triethylene glycol by Xi plane distortion, destroy the pi pi interactions, this can also be in the molecular simulation of structure optimization and energy difference calculation verification assistant. Three can be found in the hexanol in molecular self-assembly, the critical concentrations were 1.24E-6M, 1.8E-4M and 4.8E-4M, POSS-PDIH-POSS, POSS-PDIBr-POSS, alcohol / two oxygen six ring is an ideal composite solvent system, and the ideal solvent system POSS-PDITEG-POSS is THF/ water. In solution self-assembly, three molecules have wide absorption 0-0/ and 0-1 ratio decreases and the epsilon epsilon two dimer formation characteristics, but the fluorescence performance of aggregates, only POSS-PDIH-POSS has launched both significant quenching, two together they form the body configuration There can be a difference.
3. of the three molecules through the method of phase separation to form specific morphologies of aggregates, fluorescence, polarizing microscope and SEM, TEM and other measurements showed that POSS-PDIH-POSS and POSS-PDIBr-POSS formed in the crystal acicular crystal, two molecules with two dimers as least element to form a discontinuous stack, POSS-PDIH-POSS is J two dimer POSS-PDIBr-POSS due to large displacement and the long axis of the naphthalene ring is formed between the two type H dimer, which is probably the reason why the POSS-PDIBr-POSS crystal has unique photophysical properties: compared to the POSS-PDIH-POSS blue shift of fluorescence emission spectra and fluorescence quantum yield is low, the blue shift phenomenon is different from the bay a bromination, redshift side group is linear the chain of PDI. And the POSS-PDITEG-POSS is formed by spherical particles flake aggregates piled into the high resolution TEM can be observed by the sheet-like aggregate spacing is 2.7nm a darker line Take (POSS nanoparticles) were assembled into orderly. Through the analysis of the temperature dependence of the FTIR and the formation of metastable ordered structure, and the characteristics of POSS-PDI-POSS two dimer stacking as primitives, speculated that the formation mechanism is: two molecules to form a dimer after first stacking layer, then layers stack, finally due to the combined effect of hydrophobic hydrogen bond and formation of globular crystals.

【学位授予单位】：东华大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ241.5;TB383.1

【共引文献】