【作者】 王琳琳；

【导师】 冯圣玉；

【作者基本信息】 山东大学 ， 高分子化学与物理， 2013， 硕士

【摘要】 聚集诱导发光(AIE)指的是,在溶液中无发光性质的有机化合物在聚集态或固态下具有发光的现象。聚集诱导发光增强(AIEE)指的是,与溶液发光相比,发光分子在聚集态或固态下具有更强发光效率的现象。常见的荧光化合物,尽管在溶液中具有较高的荧光量子效率,由于分子间相互作用会导致固体荧光效率降低。AIE/AIEE现象的发现,可以从根本上克服化合物这种聚集诱导猝灭(ACQ)的缺点,从而利于光电材料的设计与应用。官能化硅烷,即硅原子上带有官能团的小分子有机硅化合物。与传统的有机化合物小分子相比,官能化硅烷通常具有热稳定性高,光学纯度高等优异的光电性质,同时由于其合成方法简单,故被广泛应用于有机发光器件(OLEDs)、化学传感、生物标记等各个领域。因此,本文希望发展一系列新型的具有AIE/AIEE性质的腈基官能化硅烷,并研究其AIE/AIEE的机理,同时探索此类官能化硅烷的潜在应用。基于此研究目的,本课题开展了如下工作：1.合成了两种腈基官能化硅烷,二(4-腈苯基乙炔基)二甲基硅烷(CN-1)和二(4-腈苯基乙炔基)二苯基硅烷(CN-2)。利用红外、核磁、元素分析、高分辨质谱及X射线单晶衍射对最终产物进行表征与结构分析,提供了一条将氰基官能团引入到硅烷中的有效途径。为了研究两种苯乙炔基桥连的氰基官能化硅烷的AIEE性质,测试其在水/四氢呋喃混合溶液的荧光发射光谱、紫外吸收光谱及聚集态下的电镜形貌,比较了4-氰基苯乙炔基团及硅核对此类化合物光学行为的影响。同时,通过单晶结构与分子轨道的理论计算尝试对AIEE现象进行机理解释。另外,基于氰基官能化硅烷的荧光发光行为,通过荧光滴定实验,测试了氰基官能化硅烷对TNT的荧光响应,希望发展一种高灵敏度的TNT检测方法。2.为了扩大AIE/AIEE体系的种类,首先合成了一系列溴苯基硅烷的前躯体,再通过Suzuki高效反应制备一系列不同枝数、不同取代基的二联苯桥连氰基官能化硅烷：二(4-腈基二联苯基)二甲基硅烷、二(4-腈基二联苯基)二苯基硅烷、三(4-腈基二联苯基)甲基硅烷、三(4-腈基二联苯基)苯基硅烷、四(4-腈基二联苯基)硅烷。利用红外、核磁、元素分析及高分辨质谱对产物进行结构表征与分析,并通过TGA和DSC测试这一系列的氰基官能化硅烷的热稳定性。紫外-可见吸收及荧光性能测试表明,这些ACQ化合物具有特殊的AIEE效应。进一步研究表明,这些化合物在紫外到蓝光区域有很强的荧光发射与较高的固体荧光量子效率,并且具有较低的HOMO能级(6.57eV到6.79eV)与较大的]HOMO-LUMO能量差(约4.74eV),故可作为空穴阻挡材料或蓝光发光材料应用于有机电致发光领域。另外,基于氰基官能化硅烷的光学行为,测试了其对二苯胺(DPA)的荧光与紫外响应,希望发展一种高灵敏度的DPA检测方法。更多还原

【Abstract】 Owing to the intermolecular interactions and the corresponding nonradiative decay, the fluorescence efficiency of organic luminescent materials often decreases in the solid state. This aggregation-caused emission quenching (ACQ) has seriously obstructed advancement in the development of efficient organic light-emitting diodes (OLEDs), chemosensors, biosensors, etc. To overcome this problem, considerable research has focused on the synthesis of compounds possessing aggregation-induced emission (AIE) or aggregation-induced emission enhancement (AIEE) properties. These solid-state, highly emissive organic materials are regarded as competitive candidates for practical use as highly emissive materials, and seem especially ideal for OLEDs. Functionalized silanes are defined as the small organosilicon compounds with functional groups, and compared to conventional carbon compounds, they have many advantages, such as more accessible synthesis, high thermal stability and high color purity. Thus they have been applied in extensive areas, including organic light emitting devices, chemical sensors or biosensors and so on. In this dissertation, investigations have been carried out and focused on the design, synthesis, AIEE properties and application of cyano functionalized silanes. The main contents are as follows:1. Two kinds of phenylethynyl-bridged cyano functionalized silanes, namely, bis(4-cyanophenylethynyl)dimethylsilane (CN-1) and bis(4-cyanophenylethynyl)diphenylsilane (CN-2), have been synthesized and characterized by FTIR, NMR, elementary analysis, HRMS and XRD, which provides a method to introduce cyano group into functionalized silanes. To investigate the AIEE property, the fluorescent behaviors, UV-vis absorption spectra and SEM were measured in the mixture solution of water/THF. By comparison with4-((trimethylsilyl)ethynyl)benzonitrile (1) and4-ethynybenzonitrile (2),4-cyanophenylethynyl unit is found to be the structure base to induce the AIEE phenomenon and the silicon core may enhance the AIEE effect. By crystal structure analysis and theoretical calculation, the AIEE mechanism was tried to obtain. Moreover, both CN-1and CN-2showed the obvious quenching response for2,4,6-trinitrotoluene (TNT) in THF solution, indicating their practical application in explosive detection for TNT.2. To broden the AIE/AIEE compounds, a series of diphenyl-bridged cyano functionalized silanes, namely, bis(4-cyanodiphenyl)dimethylsilane (2me), bis(4-cyanodiphenyl)diphenylsilane (2ph), tri(4-cyanodiphenyl)methylsilane (3me), tri(4-cyanodiphenyl)phenylsilane(3ph) and tetra(4-cyanodiphenyl)silane (4ph) have been synthesized by Suzuki coupling reaction using bromophenyl silanes as the starting materials. These compounds were well characterized by FTIR, NMR, elementary analysis and HRMS, and the thermal stability was measured by TGA and DSC. The optical analysis shows that these cyano functionalized silanes have unique AIEE property. These compounds are fluorescent with emission in the region of violet to blue, and possess large HOMO-LUMO energy gaps ranging from4.7377eV to4.7481eV. Thus they could be potentially used as blue emitters or hole blocking materials in OLEDs. Furthermore, these compounds all showed the obvious fluorescence quenching and ultraviolet (UV) absorption enhancement response for diphenylamine (DPA) in dicholomethane solution, indicating their potentially practical application in DPA detection.更多还原