| Project/Area Number |
12440208
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
分離・精製・検出法
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| Research Institution | Tohoku University |
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Principal Investigator |
HAYASHITA Takashi Tohoku University, Dept. of Chem., Associate Professor, 大学院・理学研究科, 助教授 (70183564)
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| Co-Investigator(Kenkyū-buntansha) |
NISHIZAWA Seiichi Tohoku University, Dept. of Chem., Research Associate, 大学院・理学研究科, 助手 (40281969)
UCHIDA Tatsuya Tohoku University, Dept. of Chem., Research Associate, 大学院・理学研究科, 助手 (30261548)
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥14,700,000 (Direct Cost: ¥14,700,000)
Fiscal Year 2001: ¥4,700,000 (Direct Cost: ¥4,700,000)
Fiscal Year 2000: ¥10,000,000 (Direct Cost: ¥10,000,000)
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| Keywords | Supramolecular chemistry / Molecular complex / Sensor / Cyclodextrin / Crown ether probe / Boronic acid probe / Alkali metal ion recognition / Sugar rcognition / ボロン酸プローブ |
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| Research Abstract |
This study reports the supramolecular function of fluorescent probe/cyclodextrin (CyD) complexes for ion and molecule recognition in water. Benzo-15-crown-5 fluoroionophores, Cn-15C5 (n=1,3,5), with different alkyl spacer lengths were first examined to develop supramolecular Cn-15C5/γ-CyD complex sensors for alkali metal-ion recognition in water. In organic solutions, C3-15C5 shows moderate Na^+ selectivity based on 1:1 complex formation. However, the C3-15C5/γ-CyD complex is found to selectively respond to K^+ ion in water and to exhibit pyrene dimer emission. An equilibrium analysis of the γ-CyD inclusion complexes in water reveals that the major component for the dimer emission is a 2:1:1 complex of C3-15C5 with K^+ and γ-CyD. Although the K^+ sensitivity of the C5-15C5/γ-CyD complex is comparable to that of the C3-15C5/γ-CyD complex, it also responds to Na^+. The fluoroionophore C1-15C5, which has the shortest methylene spacer, exhibits no response to alkali metal cations in the presence of γ-CyD. Thus, the response function is strongly affected by the alkyl spacer length of Cn-15C5, and the highest K^+ selectivity in water is obtained for the C3-15C5/γ-CyD complex. The boronic acid fluoroionophore C4-PB/β-CyD complex binds sugars and produces increased fluorescence emission in water. A pH-fluorescence profile for the C4-PB/β-CyD complex reveals that the fluorescence intensity increases upon the formation of the boronate conjugate base. Upon the addition of fructose, the apparent pK_a decreases to a lower pH, resulting in increased fluorescence at neutral pH. The fluorescence emission response of the C4-PB/β-CyD complex upon sugar binding appears to be due to suppression of the photoinduced electron transfer (PET) from the pyrene donor to the trigonal arylboronic acid acceptor.
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