芴及芴酮类化合物聚集诱导发光及固态荧光转换性质研究

发布时间：2018-03-12 16:34

本文选题：聚集诱导发光　切入点：激基缔合物　出处：《西北农林科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：近年来,有机荧光材料在光化学研究领域和光电子设备领域引起了广泛的关注,特别是具有刺激响应的荧光材料。由于很多应用于实际的有机荧光材料都是以固态或薄膜状态存在,因此化合物在聚集态就需要具有较高的荧光量子产率。但是,一般的有机发光化合物在稀溶液具有较高的荧光效率,一旦形成聚集态荧光就会急剧减弱甚至直接淬灭,这就是所谓的“聚集诱导猝灭现象(ACQ)”。很多科研工作者最初使用一些方法使其在聚集态不再猝灭,但最终的结果都不是很理想。直到发现聚集诱导发光(AIE)现象,才给固态荧光材料的设计和合成提供了新的思路。近些年发展起来的刺激响应型有机固体荧光智能材料在信息存贮、防伪、安全墨水等领域展示出非常大的潜在用途。本课题组前期研究显示,芴酮类分子在AIE和刺激响应的荧光转换方面展现出优良的性能。本论文在前期研究基础之上,对芴酮单元进行结构改进与扩展,设计合成了一系列新型的AIE分子和刺激响应的固体荧光转换分子,并着重研究了它们的AIE机理及其结构与性能之间的关系,取得了如下创新性的成果:1.设计合成了四种芳基取代的芴酮化合物,分别为DPF、PDOF、DDOF和NDOF,这些化合物具有典型的AIE性质,并且具有较高的荧光量子产率。在分子聚集的过程中,荧光强度逐渐增强的同时还伴随着约160 nm的红移。我们通过单晶结构和理论计算揭示了AIE机理。在分子堆积图中,我们发现每两个分子之间通过氢键形成二聚体,激发后形成激基缔合物。我们认为红移现象来源于激基缔合物。另外,光谱特征显示了化合物PDOF、DDOF和NDOF相较于DPF更容易形成激基缔合物。2.设计合成了四个对称和不对称的噻吩取代芴酮衍生物,分别为CTPF、ATPF、BTPF和ETPF。这四个化合物都具有高的荧光量子产率和典型的AIE性质。分子聚集过程不仅仅使荧光发射峰增强,还使发射峰的位置相对于它们的单分子发射峰来说有170 nm的红移。单晶结构表明,上下两个临近的分子通过π-π相互作用形成一个静态的激基缔合物,我们认为红移现象主要来源于静态激基缔合物的形成。另外,我们通过收集ATPF单分子和ATPF二聚体的分子轨道能量,理论计算结果与吸收光谱和发射光谱数据吻合。3.设计合成了芴类化合物MDPF,此化合物在溶液中和固体条件下均展示了高的发光效率。通过溶剂缓慢挥发法和溶剂分层法培养单晶,最终得到三种具有不同荧光发射的单晶G-MDPF、B-MDPF和V-MDPF。其中蓝色的B-MDPF通过加热可以变成紫色,而黄色的G-MDPF通过加热可以变为蓝色。通过XRD数据可知,相互变色过程是晶相与晶相之间的转变。为了探究荧光转换机理,我们解析单晶结构得知,不同颜色的单晶内部是不同的堆积模式,存在不同的激发下的电荷转移途径,导致其不同的荧光颜色。
[Abstract]:In recent years, organic fluorescent materials have attracted wide attention in the field of photochemistry and optoelectronic equipment. Because many of the organic fluorescent materials used in practical applications exist in solid or thin film state, it is necessary for the compounds to have high fluorescence quantum yield in the aggregate state. The general organic luminescent compounds have high fluorescence efficiency in dilute solution, and once they form the aggregate state, the fluorescence will weaken sharply or even be quenched directly. This is the so-called "agglomeration induced quenching phenomenon". Many researchers initially used methods to make it no longer quench in the aggregate state, but the end result was not ideal. Until the AIE-induced aggregation phenomenon was discovered, It provides a new idea for the design and synthesis of solid-state fluorescent materials. In recent years, stimulus-responsive organic solid-state fluorescent smart materials are stored in information, and anti-counterfeiting. Safety ink and other fields show great potential applications. Our previous studies show that fluorenone molecules exhibit excellent performance in AIE and fluorescence conversion of stimuli response. A series of novel AIE molecules and stimulus-responsive solid-state fluorescence conversion molecules were designed and synthesized by improving and extending the structure of fluorenone units. The AIE mechanism and the relationship between structure and properties of these molecules were studied. Four aryl substituted fluorenone compounds were designed and synthesized. They are DPFN PDOFN DDOF and NDOF respectively. These compounds have typical AIE properties and high fluorescence quantum yield. The fluorescence intensity is gradually enhanced and accompanied by a red shift of about 160nm. We reveal the mechanism of AIE by single crystal structure and theoretical calculation. In the molecular stacking diagram, we find that the dimer is formed by hydrogen bonding between every two molecules. We think that the red shift phenomenon comes from the excimer association complex. In addition, Spectral characteristics show that the compounds PDOF-DDOF and NDOF are more likely to form excimer complexes than DPF compounds. Four symmetric and asymmetric thiophene substituted fluorenone derivatives have been designed and synthesized. These four compounds have high fluorescence quantum yield and typical AIE properties. The molecular aggregation process not only enhances the fluorescence emission peak, but also increases the fluorescence emission peak. The position of the emission peaks is also red shifted by 170 nm relative to their monolayer emission peaks. The single crystal structure indicates that the upper and lower adjacent molecules form a static excimer by 蟺-蟺 interaction. We believe that the redshift is mainly due to the formation of static excimer complexes. In addition, we collect the molecular orbital energy of ATPF monolayers and ATPF dimers. The theoretical calculation results are in agreement with the absorption and emission spectra data. 3. The fluorene compound MDPFs have been designed and synthesized. The compounds exhibit high luminescence efficiency under the conditions of solution and solid. The single crystals are grown by solvent slow volatilization method and solvent stratification method. Finally, three kinds of single crystals with different fluorescence emission, G-MDPF B-MDPF and V-MDPPF, were obtained. The blue B-MDPF can become purple by heating, and the yellow G-MDPF can change to blue by heating. In order to study the mechanism of fluorescence conversion, we have analyzed the structure of single crystal and found that there are different stacking modes in different color single crystals, and there are different charge transfer pathways under different excitations. Causes its different fluorescence color.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O621.22

【参考文献】