| Summary: | 博士 === 國立交通大學 === 應用化學系所 === 96 === This thesis presents the design and synthesis of chromogenic and fluorogenic calix[4]arene derivatives as chemosensors for metal ions.
A novel chromogenic calix[4]arene 7 which has within a molecule both the triazoles and hydroxyl azophenols as the metal-binding sites and the azophenol moiety as a coloration site was designed and synthesized. Calix[4]arene 7 is highly sensitive to Ca2+ and Pb2+ ions which can be detected by the naked eye. Furthermore, the association constants for the 1:1 complexes of 7•Ca2+ and 7•Pb2+ were determined to be 7.06 �e 104 M-1 and 8.57 �e 103 M-1, respectively.
A novel fluorescent on-off switchable chemosensor 15 with two different types of cationic binding sites was synthesized, which composed of a triazole-modified calix[4]crown in the 1,3-alternate conformation. Among fifteen metal ions examined, the fluorescence of 15 was strongly quenched by Hg2+, Cu2+, Cr3+, and Pb2+, respectively; however, the revival of emission from these strongly quenched complexes was solely observed by addition of K+ ion to the 15•Pb2+ complex. Thus, metal ion exchange can trigger an on-off switchable fluorescent chemosensor.
We have designed a series of lower-rim anthraceneisoxazolylmethyl substituted calix[4]arenes 22-25 as chemodosimeters for Cu2+ ion. Stern-Volmer plots from steady state fluorescence quenching and lifetime measurements revealed that a static quenching mechanism is operative in the molecular system. Cyclic Voltammetry (CV), EPR, fluorescence measurement and 1H NMR titration experiments supported that these fluoroionophores 22-25 are Cu2+ selective chemodosimeters.
Finally, we plan to immobilize the potentially useful calix[4]arene sensors onto the silica gel surface for the sequestration of metal ions. Cu(I)-catalyzed 1,3-dipolar cycloaddition reaction of the N3-material 34 and dipropargyloxy-azocalix[4]arene 3 in the Click Chemistry condition afforded the 1,2,3-triazole modified calix[4]arene-material 36. Then, we will examine the abilities of the 1,2,3-triazole modified calix[4]arene-material to remove metal cations from aqueous solution.
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