有机染料的设计、合成及在光化学传感方面的应用

【作者】 成云飞；

【导师】 李富友； 黄春辉；

【作者基本信息】 复旦大学 ， 无机化学， 2007， 博士

【摘要】 荧光化学传感器和比色化学传感器由于具有较高的灵敏度、可利用光纤技术实现远距离实时检测、实现裸眼识别等优点，近年来引起了人们极大的兴趣。染料分子由于具有较强的生色能力，在加入底物过程中，通常会在可见光区范围发生紫外可见吸收光谱和荧光光谱的变化。因此，本论文设计、合成了一系列有机染料，并研究了其在离子光化学传感方面的应用。1．设计合成了偶氮喹啉苯酯衍生物1-4（见图A1），并研究了与Hg²⁺作用前后化合物的光物理性质的变化。实验结果表明，偶氮基团的引入改善了喹啉苯酯化合物的生色能力。苯环上4-位取代基推电子能力的增强不仅使得化合物1-3的吸收光谱发生红移，而且对化合物和Hg²⁺配位后的光谱变化有很大影响。对于含推电子基（-OCH₃，-N（CH₃）₂）的化合物2和3来说，Hg²⁺的加入使化合物由D-π-D结构转变为D-π-A结构，增加了分子内电荷转移的程度，导致化合物吸收光谱的红移；而对于含吸电子基（-NO₂）的化合物4来说，Hg²⁺的加入使化合物由D-π-A结构转变为A-π-A结构，减小了分子内电荷转移的程度，从而导致化合物吸收光谱的蓝移。强推电子基（-N（CH₃）₂）的引入将化合物3在加入Hg²⁺前后的光谱调节至可见光区范围内，使其可用于Hg²⁺的裸眼检测。其它金属阳离子的存在不干扰Hg²⁺的检测。紫外吸收光谱和¹H NMR谱均证实化合物与Hg²⁺的键合部位是喹啉N原子与酯基O原子。2．设计合成了罗丹明衍生物1-3（见图A2），研究了加入Hg²⁺前后化合物的光物理性质的变化。实验结果表明，在pH为中性的缓冲溶液中，加入Hg²⁺前，化合物1-3的紫外可见吸收谱图的吸收峰强度很弱，对应的荧光光谱发射峰也很弱，此时化合物为关环态；而加入Hg²⁺后，紫外可见吸收谱图上位于555 nm附近分别出现了明显的吸收峰；对应的荧光光谱在510 nm波长激发下位于580 nm附近也出现了明显的发射峰，化合物由关环态转化为开环态。相应的颜色和荧光均发生了明显的变化：颜色由无色变为明显的红色；荧光颜色在365 nm波长激发下由无色变为橙红色。化合物1相比于化合物2和3对Hg²⁺具有更好的选择识别性能，其它金属离子的存在不干扰化合物1对Hg²⁺的检测。化合物1有望发展为同时具有吸收和荧光发射输出信号的Hg²⁺化学传感器。3．设计合成了具有不同共轭结构的偶氮羟基喹啉衍生物1-3（见图A3），研究了加入阴离子前后化合物的光物理性质的变化。实验结果表明，偶氮基团的引入改善了8-羟基喹啉的生色能力，并且在乙腈溶液中随着取代基由苯基变为萘基和蒽基时，化合物的吸收光谱发生红移。结合吸收光谱数据和晶体结构数据可以得出，在乙腈溶液中化合物的光物理性质主要取决于共轭结构，而在固态条件下化合物的光物理性质受共轭结构、分子面间距、二面角以及氢键作用的综合影响。多环芳烃的引入能够在一定程度上改善化合物对阴离子的键合能力，使化合物均对F有较好的响应，并可达到裸眼识别。¹H NMR表明酚羟基是偶氮喹啉衍生物响应阴离子的关键部位。4．设计合成了半菁染料1-4（见图A4），研究了这四个化合物在加入阴离子前后的光物理性质。在加入碱性较大的阴离子（F和AcO-）后，化合物1-4的乙腈溶液的紫外可见吸收光谱均发生了明显的红移，表明1-4是一类较好的阴离子化学传感器。设计合成了一个查尔酮化合物5，加入碱性较大的阴离子（F和AcO^-）后，紫外可见吸收光谱和荧光光谱均发生变化，有望发展为荧光和生色双功能阴离子传感器。5．由于方酸染料与巯基的反应可破坏方酸染料的共轭结构，而加入Hg²⁺后，巯基与Hg²⁺相互作用可置换出方酸染料。基于这个置换反应，在第六章中，制备了有机／无机杂化介孔材料SQ／SBA-15（见图A5），可同时用于Hg²⁺的检测和分离。其它金属阳离子的存在不干扰SQ／SBA-15对Hg²⁺的检测，SQ／SBA-15有望发展为同时用于Hg²⁺的检测和分离的有机／无机杂化材料。更多还原

【Abstract】 Fluorescent and colorimetric chemosensors in selectively recognizing ions and molecules are of great interest in supramolecular chemistry. The advantages of fluorescence chemosensors are high selectivity, sensitivity and simplicity. Colorimetric sensors are popular due to their capability to detect analyte by the naked eye without resorting to any expensive instruments. In this thesis, a series of new fluorescent and colorimetric chemosensors were synthesized and investigated for their applications in the detection of Hg²⁺ and anions. The details are as follows:1. Four 8-hydroxyquinoline benzoate derivatives with diverse azo substituents 1-4 （see Fig. A1） were synthesized by diazo-reaction of 2-methyl-8-hydroxyquinoline with various arylamines, followed by esterification with benzoyl chloride. All the products allowed selective responding to Hg²⁺, which was confirmed by Uv-vis absorption spectra. Different spectral changes were observed for these compounds with electron-donating substituent （bathochromic shift） or electron-withdrawing substituent （hypsochromic shift）. Particularly, obvious color change was found for 5-（4-dimethylaminophenylazo） -2-methylquinolin-8-yl benzoate （3） in the presence of Hg²⁺, which made it possible for distinguishing Hg²⁺ from other metal ions by naked eye.2. Three rhodamine B derivatives 1-3 （see Fig. A2） were synthesized and studied as turn-on fluorescent chemosensors for Hg²⁺. When Hg²⁺ was added, the solution of these compounds turned from colorless to red, corresponding to apparent fluorescent change from colorless to red-orange with excitation wavelength at 365 nm. Especially, a rhodamine B derivative with quinoline group （1） displayed highly selectivity for Hg²⁺ over other metal ions, which made it possible for distinguishing Hg²⁺ from other metal ions by naked eye.3. Three 8-hydroxyquinoline azo derivatives 1-3 （see Fig. A3） with diverse conjugated structures were synthesized and studied to chromogenically detect anions. All these dyes allowed detection for fluoride anion in CH3CN via instance deprotonation of compounds, which was confirmed by UV-vis absorption and H NMR spectra. The chromogenic responding ability increases as the substituent changes from phenyl to naphthyl or anthryl. This phenomenon is likely to be related to the enhancement of intramolecular charge transfer （ICT） induced by extension of conjugated structure. 4. Four hemicyanine derivatives 1-4 （see Fig. A4） with diverse conjugated structures were synthesized and studied to chromogenically detect anions. All these dyes allowed detection for anions such as F^- and AcO^- in CH₃CN, which is likely to be related to the enhancement of intramolecular charge transfer （ICT） induced by instance deprotonation of compounds. In addition, a chalcone derivative was synthesized as fluorescent and colorimetric chemosensor for anions such as F^- and AcO^-.5. Mesoporous SQ/SBA-15 on the basis of the interaction of squaraine dye and mercaptol was designed and synthesized. This chemodosimeter system displayed highly selectivity for Hg²⁺ over other metal ions, corresponding to apparent color change from colorless to blue, which made it possible for distinguishing Hg²⁺ from other metal ions by naked eye. Moreover, SQ/SBA-15 could adsorb and separate Hg²⁺ from solution. This route based on guest-induced dye release methods might be of interest as a new route for the design of new and improved regenerative sensor molecules.更多还原