【作者】 王婷；

【导师】 张树伟；

【作者基本信息】 扬州大学 ， 化学， 2023， 硕士

【摘要】 传统有机发光材料普遍存在聚集荧光淬灭(Aggregation-induced fluorescence quenching,ACQ)现象,从而导致其在实际应用中受限。唐本忠院士课题组于2001年首次提出有机荧光分子的聚集诱导发光(Aggregation-induced emission,AIE)现象,AIE活性材料在聚集态时,由于其分子的排列形式、空间构象以及电子转移等因素的变化,而表现出独特的荧光增强现象。这一现象的发现有效解决了传统有机发光材料在聚集状态下ACQ的问题。该现象被提出至今,AIE活性材料在智能记忆材料、痕量检测、荧光分子探针、生物成像和有机发光二极管等领域发挥出巨大的应用潜力。本文利用Suzuki交叉偶联和Knoevenagel缩合等反应,设计合成了多种新型的AIE有机荧光分子,并对其光学性质以及在pH方面的检测等方面做了相关探究。具体开展内容如下:1.基于喹啉-丙二腈(QM)分子内电荷转移(ICT)型AIE活性分子的合成。通过调节给体结构部分取代基的种类和位置,制备了一系列具有AIE活性的有机荧光分子,并进一步探究了取代基对其光学性质的影响。结果表明强给电子取代基的引入使AIE分子的荧光发射增强,特别是-OH的引入对荧光增强的效果最为显著,而强拉电子取代基引入时导致荧光减弱。该工作表明取代基种类和位置与AIE分子的光学性质密切相关,为此类材料的制备提供了一定的研究基础。2.利用传统的AIE荧光团四苯乙烯(TPE)和2-(2-羟基苯基)-3H-喹唑啉-4-酮(HPQ)相结合,设计合成了具有强烈荧光、大斯托克斯位移(～200nm)和光稳定性良好的AIE化合物HTPQ-OH。化合物HTPQ-OH可用于pH的检测。另外,该化合物被2,4-二硝基苯磺酰基修饰得到荧光发射“开关”型的化合物HTPQ-thiol,对生物硫醇具有一定的识别性。3.我们以经典AIE活性荧光团四苯乙烯(TPE)为母体开发了一种新型pH响应的AIE荧光探针TPE-DCP。该荧光探针以TPE为AIE活性基团,二氰基异佛尔酮为电子受体,羟基为ICT效应给体和pH响应基团。研究结果表明,TPE-DCP展现出良好的AIE性质和大的Stokes位移,该探针的荧光强度与pH值在8.5至4.5范围内呈现线性关系,其pKa为6.82。同时,该探针具有良好的抗干扰性和低细胞毒性,已被成功地应用于细胞内pH变化的检测。更多还原

【Abstract】 Traditional organic light-emitting materials generally have the phenomenon of aggregation-induced fluorescence quenching(ACQ),which does not emit light or emits very weak in the aggregated state,resulting in their limited practical application.In 2001,Benzhong Tang’s research group first proposed the phenomenon of aggregation-induced emission(AIE)of organic fluorescent molecules,and AIE active materials showed unique fluorescence enhancement phenomena due to changes in molecular arrangement,spatial conformation and electron transfer when they were aggregated.The discovery of this phenomenon effectively solves the problem of ACQ in the aggregate state of traditional organic light-emitting materials.Since then,AIE active materials have played a great number of applications in the fields of intelligent memory materials,trace detection,fluorescent molecular probes,biological imaging and organic light-emitting diodes.In this paper,a variety of novel AIE organic fluorescent molecules were designed and synthesized by using Suzuki cross-coupling and Knoevenagel condensation reactions,and their optical properties and pH detection were explored.The specific contents are as follows:1.Synthesis of AIE active molecules based on quinoline-malononitrile(QM)with intramolecular charge transfer(ICT).By adjusting the type and position of substituents in the donor structure,a series of organic fluorescent molecules with AIE activity were prepared,and the influence of substituents on their optical properties was further explored.The results show that the introduction of electron-rich substituents enhances the fluorescence emission of AIE molecules,especially the introduction of-OH while the introduction of electron-deficient substituents leads to fluorescence decreased.This work shows that the type and location of the substituents are closely related to the optical properties of AIE molecules,which provides a certain research basis for the preparation of such materials.2.Based on TPE and 2-(2-hydroxyphenyl)-3H-quinazolin-4-one(HPQ),we designed and synthesized an AIE fluorophore HTPQ-OH with strong fluorescence,large Stokes shift(～200 nm)and good photostability.HTPQ-OH could be used for pH detection.In addition,after the introduction of 2,4-dinitrobenzenesulfonyl group,we obtained a fluorescent emission "switch" type fluorescent probe HTPQ-thiol,which exhibited certain recognition for biothiols.3.We developed a novel pH-responsive AIE fluorescent probe TPE-DCP based on the classical AIE active fluorophore tetraphenylethylene(TPE).The probe used TPE as the AIE active group,dicyanoisophorone as the electron acceptor,and hydroxyl group as the ICT effect donor and pH response group.The results show that TPE-DCP exhibits good AIE properties and large Stokes shift,and the fluorescence intensity of the probe has pKa at 6.82 and a linear relationship with pH in the range of 8.5 to 4.5.Meanwhile,the probe has good anti-interference and low cytotoxicity,and has been successfully applied to monitor intracellular pH changes.更多还原