基于ESIPT机理荧光探针的设计、合成与性能研究

发布时间：2018-04-04 12:42

本文选题：荧光探针　切入点：激发态分子内质子转移　出处：《浙江大学》2017年博士论文

【摘要】：荧光探针检测具有灵敏度高、选择性好、响应迅速、检测范围宽、操作简单方便等优点,尤其是其无可比拟的实时性这一特点,结合荧光成像技术,荧光探针可以用于活细胞及活体中生物分子及生物过程的原位实时无损伤监控,因而在有机化学、高分子化学、材料化学、生命科学和医药等各个领域引起了广泛的关注和研究。本论文对探针分子进行了详细的描述和研究,通过合理的设计,简单、成熟的合成,详细、全面的表征,探索了一系列探针分子的性质及其在小分子检测方面的应用。结合文献报道和本课题组之前的工作,我们先是基于激发态分子内质子转移(ESIPT)机理和氟离子与硅反应引起硅-氧键断裂的反应设计合成了两个荧光探针SiOPI和SiOPIC。两个探针分子展现出了对氟离子快速而优异的灵敏度和选择性,尤其是SiOPI分子,有效屏蔽了氢氧根的干扰,这一点是氟离子检测领域长久以来的难点之一。通过1HNMR、29SiNMR和ESI-MS对检测过程的跟踪,我们推测出了 SiOPI与氟离子的两阶段反应机理,很好的解释了在氟离子滴定时其光物理性质的变化过程,与我们观察到的现象完美契合。这两个阶段包括硅-氧键断裂并形成t-BuPh2SiF2-的过程,以及之后过量氟离子存在时去质子化的过程。当SiOPI的硅-氧键断裂生成HOPI分子,其ESIPT机理便被激活,可以观察到一个明显的荧光红移过程。因此这两种探针分子均可用于氟离子检测,特别是SiOPI分子,展现出了很好的比率荧光的特性。比率荧光探针的选择性和灵敏度要明显高于普通探针分子,且受到外部环境的影响更小,测量数据更加准确。接着,我们介绍了两个基于ESIPT机理和光诱导电子转移(PET)机理设计合成的过氧化氢探针分子P1和P2,通过对其性能研究,我们发现这两个探针可用于在碱性环境中快速检测过氧化氢。P1的发色团HPNO的荧光发射光谱因其ESIPT机理而受到溶剂性质的显著影响。在二氯甲烷中,HPNO表现出双波长发射;当溶剂极性上升,在质子性溶剂如甲醇、DMF中其酮式异构体的发射峰减弱,烯醇式的荧光发射占主导作用;而其余三个分子在不同溶剂中则基本不受影响。接着,我们又研究了 P1和P2的发色团HPNO和B-HBO在碱性环境中去质子化的荧光性质。在体系中加入NaOH后,二者均发生荧光发射强度的改变,并分别伴随有红移或蓝移,B-HBO甚至可以观察到溶液颜色的变化,表明该分子在pH比率检测方面有着潜在的应用。而P1和P2则表现出了对碱性条件良好的耐受性,其吸收和荧光发射光谱基本没有变化。随后我们研究了 P1和P2在碱性环境下对过氧化氢的传感,发现他们均能很好的检测过氧化氢。P1在碱性环境下对过氧化氢的响应表现为比率荧光改变,而P2则表现为荧光猝灭。结合文献报道及我们的分子模拟计算结果,我们推测P2发生了 PET过程导致其荧光猝灭。两个探针均显示出了对过氧化氢优异的敏感性和选择性。此外,其明显优于其他探针分子的响应速率,为过氧化氢检测提供了新的解决方案。与P1相比,P2展现出了更好地灵敏度,而且是有报道以来的第一例BODIPY用于过氧化氢检测的荧光探针分子。文章针对氟离子和过氧化氢检测的特点,设计合成了一些探针分子,并以此为基础对这些化合物进行了大量的表征工作,并对其在相应分子检测方面的应用性进行了研究。这些工作不仅丰富了有机荧光化合物的种类,更为有机荧光探针分子在分子传感领域的应用提供了新的思路和解决方案。
[Abstract]:Fluorescence detection with high sensitivity, good selectivity, fast response, wide detection range, has the advantages of simple and convenient operation, especially the characteristics of the real-time fluorescence imaging technology combined with There is nothing comparable to this, and the fluorescent probe can be used for in situ biological molecules and biological processes of living cells and in vivo in real-time monitoring without damage, so in organic chemistry, polymer chemistry, materials chemistry, life sciences and medicine has aroused widespread concern and research. This paper makes a detailed study on the probe molecule, through reasonable design, simple and mature synthesis, detailed, comprehensive characterization, explore the properties of a series of probe molecules and its application in small molecule detection. Combined with the literature and our previous work, we first excited state intramolecular proton transfer (ESIPT) mechanism based on silicon and fluorine ion and reaction of lead Reaction design of silicon oxygen bond rupture of the synthesized two fluorescent probes SiOPI and SiOPIC. two probe molecules show for fluoride fast and excellent sensitivity and selectivity, especially SiOPI molecules, effectively shielding the hydroxyl interference, this point is one of the difficulties in the field of fluorine ion detection. Through the long long 1HNMR, 29SiNMR and ESI-MS on the detection process of tracking, we conclude that the two stage of the reaction mechanism of SiOPI and fluoride, a good explanation of the changes in the photophysical properties of fluorine ion titration, and we observed the phenomenon of perfect fit. These two stages including silicon oxygen bond rupture and the formation process of t-BuPh2SiF2-, and then there is an excess of fluoride deprotonation. When SiOPI silicon oxygen bond cleavage to generate HOPI molecules, the ESIPT mechanism is activated, can be observed an obvious fluorescence redshift. Therefore, these two kinds of probe molecules can be used for the detection of fluoride ion, especially SiOPI molecules, showing a good ratio of fluorescence. The ratio of fluorescence probe selectivity and sensitivity was higher than that of ordinary probe molecules, and influenced by the external environment of the smaller, more accurate measurement data. Then, we introduce two based on the mechanism of ESIPT and photoinduced electron transfer (PET) mechanism design and synthesis of hydrogen peroxide probe molecules P1 and P2, the performance of research, we find that the two probe can be used for spectral properties affected by the solvent due to its mechanism of ESIPT fluorescence detection of hydrogen peroxide.P1 chromophore HPNO fast in alkaline environment in dichloromethane. In HPNO, showed a dual wavelength emission; when the polarity of the solvent increased in protic solvents such as methanol, DMF emission peak of the keto isomer decreased, fluorescence emission accounted for the enol A leading role; while the remaining three molecules in different solvents is basically unaffected. Then, we also studied the fluorescence properties of P1 and P2 HPNO and B-HBO chromophore deprotonated in the alkaline environment. Adding NaOH in the system, two occurred in the fluorescence emission intensity change, and were accompanied by red shift or a blue shift, B-HBO can even observed color change, show that the molecules have potential applications in pH ratio detection. P1 and P2 showed good tolerance to alkaline conditions, the absorption and fluorescence emission spectra did not change. Then we study the P1 and P2 in alkaline environment the hydrogen peroxide sensor, found that they were good.P1 detection of hydrogen peroxide in alkaline environment in response to hydrogen peroxide showed fluorescence and P2 ratio change, there is fluorescence quenching. Combined with the literature and our points The sub simulation results, we speculate that P2 PET process resulted in the fluorescence quenching. The two probes showed excellent sensitivity and selectivity to hydrogen peroxide. In addition, the response rate was significantly better than the other probe molecules, which provides a new solution for hydrogen peroxide detection. Compared with P1, P2 showed better the sensitivity, and it is the first case of BODIPY reported since the fluorescent probe molecules for hydrogen peroxide detection. According to the characteristics of fluorine ion and hydrogen peroxide detection, some probes were designed and synthesized, and as a basis for the characterization of many of these compounds, and the corresponding molecular detection applications were studied the work not only enriches the types of organic fluorescent compounds, it provides new ideas and organic fluorescent probes used in molecular sensing fields Solution.

【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：O657.3

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