| Summary: | 碩士 === 國立交通大學 === 應用化學系分子科學碩博士班 === 99 === In this thesis, we synthesized a new chemosensor based on 1,3-alternate calix[4]arene 60 with isoxazole and triazole units which were introduced by 1,3-dipolar cycloaddition and click reaction. Followed by Mo(CO)6 mediated ring-opening reaction of isoxazole, a novel ditopic receptor calix[4]arene 61 constructed by anthrylmethyl-triazole and β-amino-α,β-unsaturated ketone groups was obtained. Two control compounds 48 and 56 were also synthesized. The metal ions binding abilities of 48, 56, and 61 toward were invesitigated by UV-vis, fluorescence and 1H-NMR spectroscopy. Using UV-Vis and fluorescence spectra for screening, we found that 61 was selective toward Na+ and Pb2+ in CHCl3/CH3CN = 1:499. Job Plot and 1H-NMR titration experiment show that the binding ratio of 61 toward Na+ and Pb2+ was 1:1, respectively.
The binding site of 61 toward Na+ and Pb2+ was proposed to be between phenolic-O and the C=O group on the β-amino-α,β-unsaturated ketone, we also found that Na+ and Pb2+ were chelated on 61 with the help of phenol at calixarene. The competitive experiment of 61 with Na+ and Pb2+ showed that even at low concertation can make the absorption and fluorescence saturated. The Ka of 61•Na+ + Pb2+ caculated by non-linear fitting method were 1.28×106 M-1, we also get the Ka of 61•Pb2+ + Na+ from non-linear fitting method is 56.9 M-1。
Futhermore, the metal ions screening of 61 by UV-vis and fluorescence experiments of 61 spectroscopy were carried out in more polar solvent. In the CHCl3/CH3OH = 1:49 solvent system, 61 was found to be selectivity toward Ag+, which caused an enhancement of its fluorescence by 4.6-fold. According to 1H-NMR titration experiment, we proposed that the binding ratio of 61 with Ag+ is 1:2. Further evidence of the formation of complex 61•(Ag+)2 came from the observation of m/z = 750 in FAB Mass spectrum. In the 1H-NMR titration experiments of control compounds 48 and 56 also showed that Ag+ can be chelated by both of β-amino-α,β-unsaturated ketone and triazole units. So we proposed that 61 can bind 2 eq of Ag+ at the same time, one at the β-amino-α,β- unsaturated ketone and the other at triazo units, to form a 1:2 complex.
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