【作者】 曹孝卫；

【导师】 林伟英；

【作者基本信息】 湖南大学 ， 有机化学， 2012， 博士

【摘要】 荧光探针是一种能够将分子间的作用关系转化成了荧光信号的工具，已经成为现代科学和医学领域，如：临床诊断，生物技术，分子生物学，生物化学，材料科学，分析和环境化学等，不可或缺的工具。香豆素，氟硼荧，罗丹明，花菁素等常见荧光染料由于优良的光学和生物性能，如：荧光量子产率高，光稳定性好，生物兼容性好等，已被广泛用作信号团荧光用于各种荧光探针的设计和合成中。随着荧光仪器和荧光成像技术的发展，荧光探针对目标物的实时在线以及空间分辨的检测功能使得荧光探针的优点更加突出，成为科学研究中的理想工具。利用常见荧光染料构建更多种类的荧光探针具有重要的意义。本论文以香豆素，罗丹明，氟硼荧，花菁素为荧光信号团，分别构建了以硫脲类物质，汞离子，氟离子，硫阴离子为目标物的荧光探针。具体内容如下：针对单官能团转移策略设计的荧光探针选择性差的问题，找到了利用双官能团转移策略设计高选择性荧光探针的方法。基于此策略，在香豆素染料上同时引入羰基和溴原子两个淬灭基团设计合成了第一个荧光增强的硫脲类探针。该探针对硫脲的检测具有很高的灵敏性和选择性，检测下限达到2.8×10-7M，而且能够检测实际环境水样与土样中的硫脲。机理研究表明，该探针与硫脲类物质作用，是通过Hantzsch’s反应生成噻唑类物质，同时移去了羰基和溴原子淬灭基团，实现了双官能团转移的目的，从而使得探针荧光增强。以上例子说明，双官能团转移策略能够用来构建更多的高选择性的荧光探针。基于汞离子的嗜硫性和亲炔性，将硫原子和炔基组成新的汞离子受体，以罗丹明染料为荧光团，设计和发展了一个新的不可逆汞离子荧光增强探针。该探针对汞离子的响应表现出荧光增强倍数大（140倍），选择性高，检测下限低，响应时间短等优点。对汞离子响应机理的初步研究表明，探针对汞离子的响应既有配位作用又有媒介催化作用。探针能够检测细胞内的汞离子说明该探针具有广泛的应用潜质。基于汞离子的嗜硫性和亲烯性，将硫原子和烯基组成新的汞离子受体，以罗丹明染料为荧光团，设计和发展了一个新的可逆汞离子荧光增强探针。该探针能在中性的几乎100%水环境中对汞离子进行可逆检测，并且具有高选择性和灵敏性,检测下限达到了27.5nM。同样的，该探针也能够能够对活细胞中的汞离子进行可逆检测。所以，该探针将具有更多的生物应用，硫原子和烯基官能构成的汞离子新配体也将用来发展更多的可逆汞离子荧光传感器。针对近红外荧光染料花菁素的荧光信号难以调节的问题，找出了利用替代置换机理调节其荧光信号的方法。花青素染料和铜离子配体8-氨基喹啉通过哌嗪连接，构建了第一个近红外荧光增强的硫离子荧光探针。该探针在水溶液环境中对硫离子选择性高，响应灵敏度高，以及适用于较广的pH值范围。这种基于过渡金属离子或者重金属离子淬灭近红外荧光的置换取代策略，将能够用于其它阴离子近红外荧光增强探针的设计。基于香豆素染料和氟硼荧染料分子内电荷转移趋势的特点，设计合成了香豆素氟硼荧新的杂化染料平台。以该新染料为荧光团进一步设计合成了氟离子比值荧光探针。该探针对氟离子响应具有紫外吸收光谱移动大（88nm），荧光比值信号增强倍数大(I472/I606=17.4)，选择性好等特点。密度泛函理论计算合理的解释了探针对氟离子响应的光谱行为。这具有分子内电荷转移信号调节机制的香豆素硼荧平台将能够用来开发更多的比值荧光探针。更多还原

【Abstract】 Fluorescent probes which can transfer the molecular recognition events into thefluorescent signal are indispensable tools in various fields of modern science andmedicine, such as clinical diagnostics, biotechnology, molecular biology,biochemistry, materials science, analytical and environmental chemistry. Thecommon dyes like coumarin, rhodamine, BODIPY and cyanine due to their goodphotophysical properties and biological activation including high fluorescentquantum yields, good light stability and biocompatible, have been widely used asfluorophores in fluorescent probes construction. With the development offluorescence spectroscopy and fluorescence imaging technology, the merits offluorescent probes in the analytical fields like real-time and spatial discriminationdetection made fluorescent probes become ideal tools for science research. So, It isof great significance to construct much more kinds of fluorescent probes using thesecommon dyes. In this paper, fluorescent probes for thioureas, mercury ions, sulfuranions and fluoride anions have been constructed using coumarin, rhodamine,BODIPY and cyanine as fluorophores respectively. The concrete contents are asfollows:A method to design fluorescent probes with high selectivity based on the doublefunctional group transformation strategy were found in order to deal with problem oflow selective probes constructed by the single functional group transformationstrategy. Based on that strategy, the first fluorescence turn-on probe for thioureashad been developed by introduced both carbonyl group and bromide atom intocoumarin dye. The probe exhibited high sensitivity and selectivity toward thioureaswith a detection limit of2.8×10-7M. Moreover, the probe could be employed tomonitor thiourea in both water and soil samples. The mechanism study shown thatthe probe taken Hantzsch reaction with thioureas to form thiazole compounds viadouble functional group transformations made fluorescence enhance. From above,the strategy should be much more useful to construct other more fluorescence probeswith high selectivity.Based on the thiophilic and π-philic properties of Hg2+, A new irreversiblefluorescence turn-on Hg2+probe have been designed and easily synthesized byintroduced new receptor of Hg2+into rhodamine dye, which was composed of thiolatom and alkyne. The probe elicited a large fluorescence enhancement (140fold) and exhibited high selectivity, low detection limit, and fast response to Hg2+. In addition,the mechanism study shown that the interaction between probe with Hg2+involved inboth coordinated and mercury-mediated catalyzed processes. The successful Hg2+imaging in living cells indicated that the probe has a great potential application.Based on the thiophilic and π-philic properties of Hg2+, A new reversiblefluorescence turn-on Hg2+probe have been designed and easily synthesized byintroduced novel receptor of Hg2+into rhodamine dye, which was composed of thiolatom and alkene. The reversible probe can detect Hg2+in the near pure aqueousmedium at neutral conditions, and exhibited high selective and sensitive to Hg2+witha detection limit of27.5nM. In addition, the probe also can detect Hg2+in livingcells in a reversible way. The reversible nature of the probe will find interestingbiological applications and the novel Hg2+receptor presented herein will be usefulfor construction of other types of reversible fluorescent Hg2+probes.In order to solve the problem of hard regulated fluorescent signal of cyaninedye, the displacement approach was proposed to regulate the fluorescent signal ofcyanine dye. The first NIR fluorescent probe for sulfide anions has been constructedby linked cyanine dye and copper ligand8-aminoquinoline with a piperazine linker.The probe in aqueous media showed high sensitivity and high selectivity towardsulfide anions, and work well in a wide pH range. Given the fact that it is relativelychallenging to switch off the fluorescence of NIR dyes, a transition-metal-baseddisplacement strategy may open an avenue for the development of NIR fluorescentsensors for a wide variety of anion targets with a significant NIR fluorescenceturn-on response.Based on the ICT character of the coumarin and BODIPY dyes, a new hybriddye, coumarin-BODIPY, was designed and synthesized. Furthermore, a novelratiometric fluorescent sensor for fluoride anions based on the newcoumarin-BODIPY platform was developed. The probe exhibited a large red shift(88nm) in absorption, a drastic ratiometric fluorescent response (I472/I606=17.4)and highly selective to fluoride anions. Density function theory and time-dependentdensity function theory calculations were conducted to rationalize the opticalresponse of the probe. The unique ICT character of the coumarin-BODIPY platformwill be widely employed to construct a wide variety of ratiometric fluorescentsensors based on the ICT signaling mechanism.更多还原