Browsing by Author "Wang, Nae-Jen"

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A highly selective fluorescent chemosensor for Ag+ based on calix[4]arene with lower-rim proximal triazolylpyrenes
(2012-08-01)
Wang, Nae-Jen
;
Sun, Chung-Ming
;
Chung, Wen-Sheng
;
應用化學系
;
Department of Applied Chemistry
Ligand 3, a calix[4]arene with lower-rim proximal triazolylpyrenes, is a ratiometric fluorescent chemosensor for Ag+ with higher sensitivity compared to ligand 5, a calix[4]arene with lower-rim distal triazolylpyrenes, and the conventional fluoroionophore with non-conjugated triazole and pyrene. In a polar protic solvent, the binding ratios for 3 center dot Ag+ was determined to be 1:1 and the association constant was found to be 7.0 x 10(3) M-1. The detection of Ag+ by ligand 3 even works in aqueous methanol solution. (C) 2012 Elsevier B.V. All rights reserved.
A specific and ratiometric chemosensor for Hg(2+) based on triazole coupled ortho-methoxyphenylazocalix[4]arene
(2011-10-21)
Wang, Nae-Jen
;
Sun, Chung-Ming
;
Chung, Wen-Sheng
;
應用化學系
;
Department of Applied Chemistry
Calix[4]arene 3, which contains two distal triazole groups on the lower rim and two distal o-methoxyphenylazo groups on the upper rim, was synthesized and found to be a specific and ratiometric sensor for Hg(2+) in a polar protic solvent. A series of o-methoxyphenylazo derivatives (3, 4, 5, 7, and 9) were synthesized, which proved that the lower-rim triazoles and the hydroxyl azophenol(s) were the major ligands for metal ion binding. Though analogues 4 and 10 showed some sensitivity for Hg(2+), compound 3 was the only ratiometric chemosensor for Hg(2+) among the series of azocalix[4]arenes synthesized in this work. The formation of 3. Hg(2+) complex was supported by UV/vis and NMR titration studies and Mass spectrometry. Based on the symmetrical features of NMR spectra of 3 center dot Hg(2+), the complex is believed to be symmetrical with respect to the calix[4]arene cavity. Furthermore, the complex was determined to be 1:1 binding stoichiometry by Job's plot, and the association constant was determined to be 4.02 x 10(3) M(-1) using Benesi-Hildebrand plot. (C) 2011 Elsevier Ltd. All rights reserved.
A specific and ratiometric chemosensor for Hg2+ based on triazole coupled ortho-methoxyphenylazocalix[4]arene
(2011-10-21)
Wang, Nae-Jen
;
Sun, Chung-Ming
;
Chung, Wen-Sheng
;
應用化學系
;
Department of Applied Chemistry
Calix[4]arene 3, which contains two distal triazole groups on the lower rim and two distal o-methoxyphenylazo groups on the upper rim, was synthesized and found to be a specific and ratiometric sensor for Hg2+ in a polar protic solvent. A series of o-methoxyphenylazo derivatives (3, 4, 5, 7, and 9) were synthesized, which proved that the lower-rim triazoles and the hydroxyl azophenol(s) were the major ligands for metal ion binding. Though analogues 4 and 10 showed some sensitivity for Hg2+, compound 3 was the only ratiometric chemosensor for Hg2+ among the series of azocalix[4]arenes synthesized in this work. The formation of 3. Hg2+ complex was supported by UV/vis and NMR titration studies and Mass spectrometry. Based on the symmetrical features of NMR spectra of 3 center dot Hg2+, the complex is believed to be symmetrical with respect to the calix[4]arene cavity. Furthermore, the complex was determined to be 1:1 binding stoichiometry by Job's plot, and the association constant was determined to be 4.02 x 10(3) M-1 using Benesi-Hildebrand plot. (C) 2011 Elsevier Ltd. All rights reserved.