【作者】 张宇；

【导师】 钱旭红； 郭祥峰；

【作者基本信息】 大连理工大学 ， 应用化学， 2009， 博士

【摘要】 锌是人体内第二富集的过渡金属，在诸如基因转录、金属酶调控、神经信号传输等许多生命过程中起着关键性作用。荧光显微成像技术作为最有效的检测手段已广泛用于生物体内锌离子的研究。成功利用此项技术的关键是设计、合成适当的锌离子荧光成像试剂。尽管已有一些商业化的锌离子探针，人们还是在努力设计、合成新的此类荧光分子，不断发现新的荧光识别原理，提高灵敏度、选择性和可靠性等，以满足各种不同的研究需要。本文基于分子内电荷转移原理设计、合成了一系列新的酰胺基喹啉衍生物，研究了这类化合物在中性缓冲溶液中对金属离子的识别性能。通过分别在酰胺基α和β位引入2-(2-羟基乙氧基)乙胺、N-(2-羟乙基)乙二胺、二(2-羟乙基)胺、苯并氮杂-15-冠-5等脂肪胺，设计、合成了七种酰胺基喹啉衍生物荧光分子探针，从中发现N-(α-(2-(2-羟乙氧基)乙胺基)乙酰基)-8-胺基喹啉(2a-1)可以比率荧光识别锌离子。2a-1与锌离子形成1：1型络合物后，其荧光量子产率增强8倍，发射波长红移75 nm；荧光颜色由青紫色变为蓝绿色，可直接观察识别过程；在活细胞内能够对锌离子进行荧光成像检测。通过分别在2a-1分子中的喹啉2和4位引入甲基、氰基、甲氧基、N-吗啉基等取代基，设计、合成了十一种酰胺基喹啉衍生物荧光分子探针。光谱研究表明，喹啉2位取代基的空阻效应将降低酰胺基喹啉与锌离子络合的稳定性；而喹啉4位取代基则导致酰胺基喹啉对锌离子检测的灵敏度最高。在喹啉2和4位引入的取代基随着其给电子能力的增加，使锌离子诱导的酰胺基喹啉的发射波长红移幅度逐渐减小，直至荧光识别信号由双波长比率变化转化为单波长强度变化。其中，N-吗啉基取代的3a-7和4a-4几乎没有背景荧光，可以线性、等比例、化学计量地荧光增强响应锌离子，其荧光量子产率分别增强141和239倍。核磁实验证实了锌离子可以诱导4a-4的酰胺基团发生去质子化，并与其形成1：1型络合物。研究了表面活性剂胶束对酰胺基喹啉识别性能的影响。在十二烷基硫酸钠胶束溶液中，2a-1的识别选择性比在常规溶液中得到进一步提高，能够专一选择性比率荧光识别锌离子；同时，荧光响应锌离子浓度范围由1-10μM拓宽至1-1000μM。更多还原

【Abstract】 Zinc is the second most abundant transition metal ion in the human body and plays an important role in various biological processes such as gene transcription, regulation of metalloenzymes, neural signal transmission, and others. The fluorescence imaging technique, which is the most effective way, is widely used for the study of Zn²⁺ in vivo. The key to successfully apply this technique is to develop appropriate fluorescent Zn²⁺ imaging reagents. Despite having many commercial Zn²⁺ sensors, people continue endeavoring to design and synthesize new ones, to find new fluorescence recognition principles, and to improve the sensitivity, selectivity, and reliability in order to satisfy various needs.In present work, a series of new carboxamidoquinoline derivatives based on the intramolecular charge transfer mechanism have been designed and synthesized. And the recognition performance for metal ions in buffer solution has been studies.Seven carboxamidoquinoline derivatives with various aliphatic amine such as 2-（2-hydroxyethoxy）ethylamine, N-（2-hydroxyethyl）ethyldiamine, bis（2-hydroxyethyl）amine, benzoazacrown ether, and others at positionαorβof the amide group, have been developed. Among them, N-（α-（2-（2-hydroxyethoxy）ethylamino）acetyl）-8-aminoquinoline （2a-l） could exhibit ratiometric fluorescent signals for Zn²⁺. After forming the 1:1 complex between 2a-1 and Zn²⁺, there are about an 8-fold increase in fluorescence quantum yield and a 75 nm red-shift of fluorescence emission. And an obviously color change from blue-purple to blue-green emission of the solution could easily be observed by the naked eye. Moreover, 2a-1 could enter living cells and signal the presence of Zn²⁺.Eleven fluorescent sensors with different substituents such as methyl, cayno, methoxyl, N-morpholinyl, and others at position 2 or 4 of the quinoline ring of 2a-l, have been synthesized. The results indicate that the Zn²⁺-binding stability of carboxamidoquinoline could be decreased by the steric hindrance effect of 2-substituents. And the highest sensitivity to Zn²⁺ of carboxamidoquinoline could be observed by introducing 4-substituents. With increasing the electron-donating intensity of substituents at position 2 or 4 of the quinoline ring, the red-shifted emission wavelength of carboxamidoquinoline induced by Zn²⁺ is gradually decreased until fluorescence signals are transformed from the dual-wavelength ratiometric changes to the single-wavelength intensity ones. Among them, 3a-7 and 4a-4 with the N-morpholinyl group show linear, stoichiometrical, and enhanced fluorescence response to Zn²⁺ without background fluorescence. There are about 141 and 239-fold enhancement in fluorescence quantum yield, respectively. ¹H-NMR titration studies indicate the deprotonation of the amide group by coordinated Zn²⁺ and the formation of the 1:1 complex between 4a-4 and Zn²⁺.The influence on the detection performance of carboxamidoquinoline in surfactant micelle has been studies. In SDS micelle solution, the selectivity of 2a-1 could be improved in comparison with that of in conventional solution. 2a-1 shows the uniquely ratiometric Zn²⁺ identification. And the recognizing Zn²⁺ ranges are expanded from 1-10μM to 1-1000μM.更多还原