【作者】 丁力；

【导师】 苏建华；

【作者基本信息】 华东理工大学 ， 应用化学， 2014， 博士

【摘要】 荧光化学传感器因其具有操作简单,成本低廉,可实时监测,高灵敏度和高选择性等一系列优点,已然成为各种客体如金属离子、阴离子、硫醇、活性氧、氨基酸、爆炸物等检测主导战略之一。多年来,化学传感器的荧光体系、分子构造和传感机制等都趋于多样性发展,而一些重要性能指标如选择性、灵敏度、响应时间、水溶性、合成难易程度及其近红外光区的应用等一直以来都是人们研究的重点和难点。典型的荧光化学传感器由“信号基团-连接基团-识别基团”构型组成,本论文以噻吨酮、芴和荧光素作为信号输出基团,通过对称和不对称侧链修饰的方法,引入不同的修饰官能团和识别基团,对化合物进行了紫外吸收和荧光发射光谱的调控,并对合成的一系列小分子化合物传感性能进行了详细的研究。第一章简述了超分子化学和分子识别的概念,重点叙述了荧光化学传感器的构造和基本机理,并对汞离子荧光化学传感器的最新研究进展进行了简要的综述,由此提出本论文的研究课题。第二章设计合成了两个以二苯胺或三苯胺为电子给体,噻吨酮为电子受体,“D-A-D”构型的化合物BDPA-TXO和BTPA-TXO。它们在不同极性的有机溶剂中表现出显著的溶剂化荧光变色现象。而且伴随着有机溶剂中水含量的不断增加,两个化合物都呈现出荧光淬灭过程,利用该性质可以将BDPA-TXO和BTPA-TXO应用于定量检测几种有机溶剂中的水含量,且BDPA-TXO二氧六环中微量水检测限达到19ppm。此外,利用两个化合物BDPA-TXO和BTPA-TXO制备的染色试纸还可以用于定性检测有机溶剂中的水含量。第三章基于汞促脱硫反应机理,设计合成了两个噻吨硫酮类反应型汞离子探针DP-TXT和BDPA-TXT。两者均可作为汞离子裸眼比色型探针：加入Hg2+前后两个化合物溶液颜色分别从橙色变为无色、紫色变为黄色。DP-TXT在乙腈-水(5：5,v/v)溶液中,BDPA-TXT在二甲基亚砜-水(9：1,v/v)溶液中对Hg2+呈现荧光增强响应,且灵敏度分别达到了21nM和75nM。同时,干扰离子测试结果表明,除了Ag+对BDPA-TXT溶液有一定的荧光增强干扰之外,两个化合物对其它金属离子都表现出了很好的抗干扰性。第四章将常见的氨基硫脲识别基团引入到噻吨酮体系中,设计合成了两个能同时对汞离子和氟离子表现出良好比色和荧光识别响应的化合物X1和Y1。汞离子或氟离子的加入会引起X1和Y1的四氢呋喃溶液吸收光谱的明显改变,尤其是氟离子导致X1和Y1最大吸收波长大范围的红移,溶液的颜色也从无色变为黄色。另外,由于X1和Y1与汞离子形成1：1配位比的络合物,促使两个化合物四氢呋喃溶液发生荧光淬灭现象。而氟离子则会促使硫脲基团脱质子化过程,同样也会促使X1和Y1发生荧光淬灭现象。第五章采用芴作为主体荧光团,侧链修饰乙酰基或硝基,并在芴荧光团另一侧连接硫脲作为识别基团,组建成“D-π-A”构型的荧光探针分子la-4a。正如预期,硝基的引入将该体系分子吸收光谱和荧光光谱都拓展至更长波长处。传感性能测试结果表明,la-4a不仅可以检测Hg2+,还可以检测CH3Hg+,并且.均具有很高的选择性和灵敏度。核磁氢谱滴定和高分辨质谱滴定实验,都很好地证明了该传感体系的识别机理是Hg2+或CH3Hg+促进脱硫,分子内环化生成咪唑啉类衍生物,从而导致化合物光谱性质发生巨大变化。第六章以荧光素为母体结构,设计合成了一个水溶性络合型铜离子探针F1。F1浓度为2.0×10-5M的二甲基亚砜-HEPES (1:99, v/v,100mM, pH7.4)溶液对Cu2+显示出良好的吸收及荧光响应,尤其是铜离子的引入对F1表现出显著的荧光淬灭效应。识别机理为F1与Cu2+形成1：1配比的络合物。F1与铜离子的络合常数确定为3.8×105M-1,铜离子理论检测限达到了2.8×10-8M。第七章结论。更多还原

【Abstract】 Owing to the operational simplicity, low cost, real time monitoring and high sensitivity, fluorescence chemosensors have become the dominant strategy for molecular recognition such as metal ions, anions, mercaptans, reactive oxygen species, amino acids and explosives. Over the years, fluorescent chemosensor systems and molecular structures, along with sensing mechanisms display the diversity of development. Some important performance parameters have been the research focus and difficulties, for instance, sensitivity, selectivity, response time, water solubility, complexity of synthesis and application in the near infrared region.Fluorescence chemosensor typically has a configuration of "signalling unit-spacer-binding site". In this thesis, we describe the rational design and synthesis of series of small molecular compounds which contain thioxanthone, fluorescein and fluorene groups serving as signalling unit. Through the method of symmetric and asymmetric side chain modifications, and also introduction of various receptor units, we regulated and controled the compounds’ optical properties such as absorption and fluorescence emission spectra, and we also detailedly studied their sensing abilities.In Chapter1, the concepts of supramolecular chemistry and molecular recognition are briefly introduced. Structures and the basic mechanisms of fluorescent chemosensor are mainly described, and the latest research progresses of fluorescent chemosensors for Hg2+are briefly reviewed. Then the research subject of this dissertation is proposed.In Chapter2, two thioxanthone-based fluorescent probes whose fluorescence properties exhibited intriguing dependence on solvent polarity were developed. In the "D-A-D" structural framing of BDPA-TXO and BTPA-TXO, the diphenylamine and triphenyl-amine groups were the donor part while the carbonyl group belonging to thioxanthone served as the acceptor part. Furthermore, the probes showed fluorescence quenching by addition of water in organic solvents. Consequently, they were found useful as fluorescence indicators for the qualitative and quantitative detection of low-level water in various solvent media. The detection limit of BDPA-TXO in dioxane reached to19ppm.In Chapter3, two thioxanthen-9-thione derivatives (DP-TXT and BDPA-TXT) were designed and synthesized based on Hg2+-induced desulfurization mechanism. Both of them can serve as naked-eye colorimetric probes for Hg2+:in the absence and presence of Hg2+, the solution color changed from orange to colorless, purple to yellow, respectively. DP-TXT in CH3CN-H2O (5:5, v/v) and BDPA-TXT in DMSO-H2O (9:1, v/v) showed significant fluorescent enhancement upon addition of Hg2+, and the detection limits for Hg2+of chemodosimeters DP-TXT and BDPA-TXT were determined to be21nM and75nM, respectively. Both of DP-TXT and BDPA-TXT exhibited specific selectivity for Hg2+over other examined metal ions except the little interference of Ag+for BDPA-TXT.In Chapter4, hydrazinecarbothioamide recognition group was introduced into thioxan-thone system, and two novel fluorogenic and chromogenic chemosensors X1and Y1for the dual-channel detection of Hg2+and F-were developed. Addition of Hg2+and F-resulted in significant changes in absorption spectra of X1and Y1in tetrahydrofuran solutions. F-leaded to a red shift of maximum absorption wavelength, and the solution color changed obviously from colorless to yellow. Furthermore, owing to the formation of a1:1complex between X1or Y1and Hg2+, as well as the deprotonation process of the thioamide protons induced by F-considerable fluorescent quenching was observed for X1and Y1after addition of Hg2+or F-In Chapter5, four novel Hg2+-selective fluorescent chemodosimeters featuring the thiourea moiety as the recognition unit were successfully designed by modifying the substituent groups of fluorene fluorophore, and the substitution of acetyl group with nitro group led to large bathochromic shifts both in absorption spectra and fluorescence spectra. They all exhibited specific sensitivity and selectivity not only for Hg2+but also CH3Hg+over other examined metal ions. The changes in their spectral properties are attributed to the transformation of thiourea unit to guanidine via Hg2+-induced and CH3Hg+-induced desulfurization reaction.In Chapter6, a fluorescein-based water-soluble chemosensor (F1) for Cu2+was designed and synthesized. It showed excellent absorbance and fluorescence response towards Cu2+, especially the addition of Cu2+induced significant fluorescence quenching. The recognition mechanism is the formation of a1:1complex between F1and Cu2+. The association constant and detection limit were determined to be3.8×105M-1and2.8×10-8M, respectively.Chapter7, conclusions.更多还原