【作者】 田茂忠；

【导师】 彭孝军；

【作者基本信息】 大连理工大学 ， 应用化学， 2008， 博士

【摘要】 荧光分子探针具有诸如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众多优点。氟硼荧（BODIPY）和罗丹明类荧光染料具有优异的光化学光物理性质，例如高的摩尔消光系数、良好的光稳定性、高的荧光量子产率等优点。因此，基于氟硼荧类和罗丹明类染料荧光分子探针的研究己引起人们越来越多的关注。设计合成了BODIPY类pH荧光分子探针M1-M6。M5对pH的响应范围是pH5．36-3．66，其它都是近中性的pH荧光分子探针，M1-M6是专一识别质子的pH荧光分子探针。同时，发现可以通过增加BODIPY染料8位亚甲基氮原子上取代基的数量、增加脂肪链取代基的链长、引入芳香烃基团等途径来降低此类染料的pK_a值，这主要是由于该氮原子附近存在的空间张力增加，使得氮原子的质子化变得更难。这种通过改变BODIPY染料8位亚甲基氮原子上的取代基来调变探针pK_a对此类pH荧光分子探针设计很有意义。基于PET原理设计合成了BODIPY类pH荧光分子探针BDTA。BDTA具有非常狭窄的pH识别范围（pH 2．00-0．65），具有很高的pH灵敏度。此外，BDTA不能够识别金属离子和阴离子，因此，BDTA是一个专一识别质子的pH荧光分子探针。基于PET原理设计合成了BODIPY类荧光化合物BPb₁，在乙腈中其最大吸收波长（496 nm）和最大发射波长（505 nm）在可见区，荧光量子产率为0．013，加入过量Pb²⁺后，pb²⁺-BPb₁络合物的荧光量子产率增大到0．693。其它常见金属离子和阴离子在乙腈中对BPb₁检测Pb²⁺没有明显的干扰。荧光增强是由于pb²⁺和受体的络合阻断了探针分子中由受体到荧光母体的光诱导电子转移（PET）。设计合成了两个罗丹明类Cu²⁺荧光增强型分子探针RB2和RG2。在Tris-HCl中性缓冲液中，RB2和RG2在常见金属离子中(Na⁺，K⁺，Mg²⁺，Ca²⁺，Ba²⁺，Mn²⁺，Cd²⁺，Cr³⁺，Co²⁺，Ni²⁺，Ag⁺，Pb²⁺，Zn²⁺，Fe³⁺，Fe²⁺，Hg²⁺)和常见阴离子(Ac^-，Cl^-，NO₃^-，H₂PO₄^-，PO₄^3-，SO₄^2-)中能够专一性地识别Cu²⁺，具有很高的灵敏度，RB2至少可以检测到1 nM Cu²⁺；RG2至少可以检测到0．1 nM Cu²⁺。加入Cu²⁺后，RB2和RG2的荧光强度分别增大约195倍和309倍。RB2、RG2对pH不敏感，可以在较宽的pH范围（包括重要的生理pH范围）内对Cu²⁺高灵敏地识别。RB2、RG2分别和Cu²⁺作用后，溶液的颜色和荧光发生明显地变化。合成了罗丹明类荧光化合物RB1和RG1。RG1对pH的响应范围是pH 4．51-0．96。随着酸度的增加（pH 4．51-0．96），RG1的吸光度和荧光强度将逐渐增大，pH降到0．96时，其荧光强度增大了约69倍，而且RG1对常见金属离子和阴离子都没有响应，所以RG1是一个高灵敏、可以专一识别质子的pH荧光分子探针。更多还原

【Abstract】 The advantages of molecular fluorescent probes 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. The boron dipyrromethene （BODIPY） dyes and Rhodamine dyes have excellent photophysics and photochemistry properties such as high molar extinction coefficient, high stability against light and chemical reactions, and high fluorescence quantum yields, etc. Therefore, the studies on fluorescence molecular probes based on BODIPY dyes and Rhodamine dyes are attracting many people’s attentions.pH fluorescent probes （M1-M6） based on BODIPY dyes have been designed and synthesized. M5 has the response signal from pH 5.36-3.66. The other compounds among them are the near-neutral pH fluorescent probes. M1-M6 are non-metal ion and non-anion sensitive. At the same time, it was found that the increase of number of substitutes, the increase of aliphatic chain length and the introduction of aromatic group on the nitrogen atom linked methene at site 8 of BODIPY dyes can reduce the pK_a of them. The main reason is the protonation of this nitrogen atom will lead to greater steric strain. The affinity of a proton to this nitrogen atom becomes more difficult. It is very significant for the design of this kind of pH fluorescent probes that the various substitutes on the nitrogen atom linked methene at site 8 of BODIPY dyes.The BODIPY fluorescent pH probe BDTA based on PET has been designed and synthesized. The probe has much narrow pH-sensitive windows （pH 2.00-0.65）. In addition, BDTA is non-metal ion and non-anion sensitive. Therefore, BDTA is a highly sensitive and selective pH fluorescent probe.The BODIPY fluorescent compound BPb₁ based on PET has been designed and synthesized. The absorption （496 nm） and emission （505 nm） wavelengths are in visible range in acetonitrile. The fluorescence quantum yields of the lead-free and lead-bound states of BPb₁ in acetonitrile are 0.013 and 0.693, respectively. Other metal ions and anions have no obvious interference for BPb₁ to detect Pb²⁺ in acetonitrile. The fluorescence enhancement is based on the blocking of photo-induced electron transfer in BPb₁ by the selective coordination of Pb²⁺ with the receptor in the probe molecule.Cu²⁺ fluorescence enhancement probes RB2 and RG2 based on rhodamine dyes have been designed and synthesized. RB2 and RG2 exhibit Cu²⁺-only sensitive among metal ions such as Na⁺ K⁺, Mg²⁺, Ca²⁺, Ba²⁺, Mn²⁺, Cd²⁺, Cr³⁺, Co²⁺, Ni²⁺, Ag⁺, Pb²⁺, Zn²⁺, Fe³⁺, Fe²⁺, Hg²⁺ and anions such as Ac^-, Cl^-, NO₃^-, H₂PO₄^-, PO₄^3-, SO₄^2-. They have extremely high sensitivity for Cu²⁺. RB2 and RG2 would detect at least 1 nM and 0.1 nM of Cu²⁺,respectively. Upon the addition of Cu²⁺, the fluorescence enhancement factors of RB2 and RG2 are ca. 195-fold and 309-fold, respectively. RB2 and RG2 are pH-insensitive Cu²⁺ fluorescent probes, which would detect Cu²⁺ effectively in a relatively wide range of pH including the significant physiological region. After the reaction between RB2 and Cu²⁺ or between RG2 and Cu²⁺, the colour and fluorescence of solution have very obvious changes.The rhodamine fluorescent compounds RB1 and RG1 have been synthesized. RG1 has the response signal from pH 4.51-0.96. The absorbance and the fluorescent emission intensity of RG1 increase continuously when the solution became more acidic from pH 4.51 to 0.96. When pH was decreased to 0.96, the fluorescence enhancement factor of RG1 is 69-fold. In addition, RG1 is non-metal ion and non-anion sensitive. Thus, RG1 is a pH fluorescent probe which has highly sensitivity and selectivity for protons.更多还原