| Interest in the design and synthesis of artificial anion receptors continues to attract the attention of supramolecular chemistry community since various anions play fundamental roles in chemical and biological process. Amide, urea, or thiourea groups have become the focus of the design and synthesis of neutral anion receptors due to their strong hydrogen-bond donor capability and lessened dependence on pH values. The supramolecular system consisting of receptor unit and fluorophore which are covalently linked, can selectively form strong hydrogen bonding with anions, and have a fluorescent response and sensing property during the recognition process. This has an important significance and application prospects for an exploitation of the sensitive fluorescence sensors based on anion recognition, the environmental monitoring of anion pollutants, the clinical diagnosis of harmful anions, and for microanalysis.In this thesis, a series of novel acyclic, cyclic and branched receptors containing amide- or (thio) urea- binding sites and fluorophore or chromophore were synthesized, and their binding and sensing properties for important anions (carboxylate, halide, phosphate, dicarboxylate) were investigated by fluorescence, UV-vis and 'H NMR spectra.1. The research progress for various types of anion receptors, and their recognizing and sensing properties for anions were reviewed.2. An amide-based fluorescent acyclic receptor (II -1) consisting of anthryl group was synthesized, and the anion binding property was studied in CHCI3 by fluorescence, UV-vis and ]H NMR spectra. Receptor II -1 selectively recognized planar anions such as acetate and p-NO2C6H4O- over halogen anions(Cr-, Br-, I-), and 1: 1 complexes were formed. In the presence of acetate and p-NO2C6H4O- anions, the fluorescence of receptor II -1 was quenched. Moreover, upon the addition of receptor II -1 into the solution of P-NO2C6H4O-, the yellow color of solution disappeared.3. Two amide-based fluorescent macrocyclic receptors (III-1 and III-2) consisting of anthryl group were synthesized, and their binding properties for anions were studied in CHCl3. Receptors (III-1 and III-2) formed 1: 1 complexes with anions, and the fluorescence of receptors IQ-1 and DI-2 was quenched due to PET mechanism. Receptor III-1 selectively recognized anions in the order F->Cl-> H2PO4-> CH3COO->>Br-, I-,and III-2 showed higher selectivity for F over other anions.4. Three novel receptors (IV-1, IV-2, IV-3) with (thio) urea and amide binding sites were synthesized, and their binding properties for anions were studied in DMSO or CHCl3. Receptors (IV-1, IV-2, and IV-3) contained fluorophore (naphthyl) or chromophore (p-nitrophenyl), formed 1:1 complexes with anions, and selectively recognized acetate anion. In particular, an obvious color change was observed, from pale yellow to red-brown, upon addition of the acetate anion to the solution of receptor IV-1 in DMSO. In the presence of anions(CH3COO-, H2PO4-, Cl-), the fluorescence intensity of receptor IV-2 was enhanced, and the fluorescence intensity of receptor IV-3 was quenched. The selective recognition of receptor IV-1 for acetate anion was better than receptor IV-2 and IV-3. The results of fluorescence and UV-vis titration indicated that the association constants of IV-1 CH3COO-, IV-2 CH3COO-, and IV-2 H2PO4- were higher in comparison with other anions (Cl-, Br-, I-,p-NO2C6H4O-,p-NO2C6H4OPO32-).5. A series of branched fluorescent receptors (V -1, V -2, V -3, and V -4) containing fluorophore (anthryl), amide and thiourea groups were synthesized, and the binding properties for dicarboxylate anions (malonate, succinate, glutarate, adipate, suberate, and sebacate) were investigated in DMSO. The dramatic changes in fluorescence spectra were observed in the presence of dicarboxylate anions. Moreover, upon addition of anions receptors V-l and V-4, not only fluorescence enhancement, but the obvious color change (from pale yellow to red) was observed by naked eye. Receptor V-l forme...
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