【作者】 赵燕；

【导师】 张晓兵；

【作者基本信息】 湖南大学 ， 分析化学， 2008， 硕士

【摘要】 分子识别作为超分子化学的重要领域,最早是由有机化学家和生物化学家在分子水平上研究生物体系中的化学问题而提出的。分子识别本质上是指主体分子（受体）对客体分子（底物）选择性结合并产生某种特定功能的过程。而它们之间的这种特定功能的过程即识别,以及伴随产生的微观环境的变化,需要借助特殊的工具才能转换成为外界所感知的信号。荧光作为这种所感知的信号具有以下优点:最高可达单分子检测的高灵敏度、能够实现开关操作、对亚微粒具有可视的亚纳米空间分辨能力和亚毫秒时间分辨能力、原位检测（荧光成像技术）以及利用光纤进行远距离检测等等。荧光分子经过特殊的设计,能够选择性识别待测物,再将这种识别信息转换成荧光信号传递给外界,具有这种功能的分子就是荧光分子探针。卟啉（H2TPP）化合物具有非常好的光学性质,是一种理想的荧光物质,具有高的荧光量子产率、大的Stokes位移、相对长的激发（> 400 nm）和发射（> 600 nm）波长,而相对长的激发和发射波长能够减少背景荧光的干扰,所以卟啉化合物是一种值得进行深入研究的荧光染料。四苯基卟啉主要用来识别汞离子,我们以四苯基卟啉为母体进行设计,合成出了一个铜离子探针—5-（2, 3, 4-三羟基苯基）-10, 15, 20-三苯基卟啉。其它离子特别是汞离子对铜离子的测定不产生干扰,从而成功地改变了其识别性能。铜离子在1.9×10^-6–5×10^-5mol/L,荧光强度的变化与铜离子的浓度呈函数关系。同时,我们设计出了N-甲基四苯基卟啉,它是在四苯基卟啉空间吡咯环上的氮修饰了一个甲基,从而又一次成功的改变了其识别性能,成为了荧光增强型的锌离子探针。除了Cu（II）和Hg（II）外,大部分的碱金属,碱土金属,和过渡金属离子对锌离子的测量几乎没什么干扰。在锌离子浓度5.0×10^-7–1.0×10^-5 mol/L范围内成线性关系。罗丹明的内酰胺螺环状结构,在长波长没有吸收,无色,无荧光;破坏内酰胺螺环状结构,在长波长有吸收,有颜色,强荧光。由于此结构上的优势,罗丹明内酰胺类化合物具有形成OFF-ON型荧光探针的潜能。在2006年,段春迎等在罗丹明6G酰肼上连接吡啶醛实现了选择性检测汞离子。基于该文提出的作用机制,我们注意到,汞离子主要与罗丹明6G吡啶醛亚胺上的N和吡啶醛上N原子络合开环,而罗丹明6G吡啶醛1-位及4-位的N,O原子贡献很少。在1997年,Czarnik等合成了铜离子选择性试剂罗丹明B酰肼。铜离子的加入,催化其水解,生成罗丹明B,铜离子主要与罗丹明B酰肼1-位及4-位的N,O原子络合,基于此,我们猜想,有可能只改变一个键,就能显著的改变识别选择性,从而实现对铜离子的选择性检测。依据上述讨论,我们设计了一个新型的罗丹明类荧光探针3。我们成功实现了改变一个键,其它都没变,显著的改变了化合物的识别选择性。且50μM的铜,荧光净增长66倍。线性范围:2.0×10^-6–1.0×10^-5 ,检测限:5.3×10^-7。更多还原

【Abstract】 Molecular recognition is the main field of Supramolecular chemistry, first advanced by organic chemist and biologic chemist when they investigate chemical problem. It in nature is the process that the host molecular integrates with guest molecular and produces a special function at this process. We need special tool to detect the process of molecular recognition and the changes of microcosmic environment during the sensing event. Fluorescent probes can transfer molecular recognition events into fluorescence signals and then make a bridge between man and molecule. The advantages of molecular fluorescence for sensing can be summarized: high sensitivity of detection down to the single molecule, "on-off’ switchability, subnanometer spatial resolution and submillisecond temporal resolution, observation in situ, remote sensing by using optical fibres, et al. Fluorescence molecular is special designed and selective recognition events, then transfer molecular recognition events into fluorescence signals and at last make a bridge between man and molecule. This is fluorescence probe molecular.Porphyrins are attractive candidates of fluorescent probes owing to their good photophysical properties with strong fluorescence, large Stokes shifts and relatively long excitation （>400 nm） and emission （>600 nm） wavelengths that minimize the effects of the background fluorescence. Tetraphenylporphine shows high selectivity toward to Hg²⁺. It is a problem to switch in the recognition preference in Tetraphenylporphine throng modification. At last, we synthesize 5-（2, 3, 4-trihydroxylphenyl）-10, 15, 20-triphenylporphyrin as a new fluorescent probe for Cu²⁺. Other ions especial Hg²⁺ do not interfere with Cu²⁺-induced fluorescence change. The probe exhibits a linear fluorescent response towards Cu²⁺ in the concentration range of 1.9×10^-6–5×10^-5mol/L. At the same time, we design and synthesize N-methyltetraphenylporphyrin throng modify a methyl in the pyrrolic nitrogens, and successfully switch in the recognition preference. The fluorescence emission intensity of N-methyltetraphenylporphyrin is remarkably enhanced upon the addition of Zn²⁺ which is attributed to the formation of 1:1 stoichiometry complexation for compound 1 with Zn²⁺. It shows a linear response toward Zn²⁺ in the concentration range of 5.0×10^-7–1.0×10^-5 mol/L.Designing chemosensors based on rhodamine spirolactams has several advantages: they display not only great absorbance and fluorescence intensity enhancement toward some specific metal ions, but also a strong color development against the colorless blank during the sensing event. So, this is an ideal modal for the design of light“off-on”switch sensors. Recently an excellent job of opening the spiro ring of rhodamine spirlactam-based chemodosimeter was published. We noticed that N（py） and N （imine） is mainly coordinate to Hg²⁺ ion, however, one carboxyl and the other nitrate anion very weakly coordinate to the Hg²⁺ ion. And another splendid job of opening the spiro ring of rhodamine was reported via Cu²⁺ ion binding at the nitrate anion, carboxyl. Bearing this in mind, we envisaged that, by altering a bond, it may be possible to carry out a rhodamine spirolactam based fluorescent probe highly selective for Cu²⁺ ions by color/fluorescence changes. On the basis of above consideration, we design a new rhodamine-based fluorescent probe 3, which displays a selective and sensitive Cu²⁺ -amplified fluorescence in neutral buffered media. Cu²⁺ displayed a 66-fold enhancement at 50μM. It shows a linear response toward Cu²⁺ in the concentration range of 2.0×10^-6–1.0×10^-5 mol/L.更多还原