Selective Potassium Ion Recognition by Benzo-15-crown-5 Fluoroionophore/γ-Cyclodextrin Complex Sensors in Water
- 27 October 2000
- journal article
- Published by American Chemical Society (ACS) in Analytical Chemistry
- Vol. 72 (23), 5841-5846
- https://doi.org/10.1021/ac000741i
Abstract
Three fluoroionophores Cn (n = 1, 3, 5), in which the crown ether unit and pyrenyl moiety are connected by a −(CH2)n− spacer, have been used to construct supramolecular Cn/γ-cyclodextrin (γ-CyD) complexes for alkali metal ion sensing in water. The Cn (n = 3, 5) are found to selectively form 2:1 complexes with K+ in the presence of γ-CyD and exhibit the pyrene dimer emission in water. Equilibrium analysis of the C3/γ-CyD complex reveals that the observed dimer emission arises from a 2:1:1 complex of C3 with K+ and γ-CyD. In the absence of K+, the fluorescence lifetimes for the dimer species ((C3)2CyD and (C3)2(CyD)2) and the monomer species (C3CyD and C3(CyD)2) are 13−18 and 130−180 ns, respectively. Upon addition of 0.10 M KCl, a rising component corresponding to pyrene excimer formation is observed at the dimer emission region. For the C3/γ-CyD complex, the apparent association constant for K+ of (3.8 ± 1.3) × 109 M-2 is only slightly affected by the presence of Na+. Although the C5/γ-CyD complex shows high sensitivity for K+, the selectivity for K+ over Na+ is lower than that of the C3/γ-CyD complex. In contrast, fluoroionophore C1 with the shortest methylene spacer exhibits no response for alkali metal cations in the presence of γ-CyD. These results demonstrate that the response function of supramolecular Cn/γ-CyD complexes is strongly affected by the methylene spacer length of Cn. The highest K+ selectivity is obtained for the C3/γ-CyD complexes in water.Keywords
This publication has 13 references indexed in Scilit:
- Fluorescence Sensing of Anions via Intramolecular Excimer Formation in a Pyrophosphate-Induced Self-Assembly of a Pyrene-Functionalized Guanidinium ReceptorJournal of the American Chemical Society, 1999
- Benzo-15-crown-5 Fluoroionophore/γ-Cyclodextrin Complex with Remarkably High Potassium Ion Sensitivity and Selectivity in WaterJournal of the American Chemical Society, 1999
- Cyclodextrin Drug Carrier SystemsChemical Reviews, 1998
- Biomimetic Reactions Catalyzed by Cyclodextrins and Their DerivativesChemical Reviews, 1998
- Self-Assembled Ionophores. An Isoguanosine-K+ OctamerJournal of the American Chemical Society, 1997
- Self-Assembling Supramolecular ComplexesChemical Reviews, 1995
- Photophysics of preassociated pyrenes in aqueous polymer solutions and in other organized mediaChemical Reviews, 1993
- Thermodynamic and kinetic data for macrocycle interactions with cations and anionsChemical Reviews, 1991
- Association dimers, excimers, and inclusion complexes of pyrene-appended .gamma.-cyclodextrinsJournal of the American Chemical Society, 1989
- Vaporization of arsenic trisulfide and the dissociation energy of arsenic monosulfideThe Journal of Physical Chemistry, 1982