• Bulletin of the Korean Chemical Society
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• v.27 no.11
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• pp.1897-1899
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• 2006

• Bulletin of the Korean Chemical Society
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• v.23 no.11
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• pp.1585-1589
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• 2002

Two novel calixarene-based fluoroionophores were synthesized. Their conformations were confirmed to 1,3-alternate by X-ray crystal structures. From CHEF by blocking the PET mechanism in fluorescence spectra, we observed $In^{3+}$ and $Pb^{2+}$ selectivity over other metal ions. For $In^{3+}$ion, calix[4]-bis-azacrown-5 showed about 20 times more sensitive than calix[4]-mono-azacrown-5 because the source of the binding selectivity comes from the calixarene framework and azacrown ligand by controlling the fluorescence and PET mechanisms as-sociated with the amine moiety.

• Bulletin of the Korean Chemical Society
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• v.30 no.6
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• pp.1401-1404
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• 2009

• Journal of the Korean Chemical Society
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• v.39 no.2
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• pp.114-117
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• 1995

• Journal of the Korean Chemical Society
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• v.35 no.6
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• pp.753-755
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• 1991

• Bulletin of the Korean Chemical Society
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• v.25 no.8
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• pp.1244-1246
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• 2004

• Bulletin of the Korean Chemical Society
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• v.31 no.4
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• pp.1014-1016
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• 2010

• Polymer(Korea)
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• v.30 no.5
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• pp.426-431
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• 2006

Novel azacrown ether containing blue -light emitting anthracene fluorophore, 9,10-bis [p-(1-aza-18-crown-6)methylphenyl] anthracene (3) and N,N-bis [9-(p-methylphenyl) anthracenyl-methyl] -1,6-diaza-18-crown-6 (4) were prepared by reacting anthracene derivatives 1 and 2 with mono- and diaza-18-crown-6, respectively Also, crown ether containing fluorophore copolymer (5) were prepared by reacting 1,6-diaza-18-crown-6 with 1. Their fluorescence emission spectral studies were investigated by binding group I, group II and various metal cations. The fluorophores showed an absorption at ${\lambda}_{max}$= 372 nm and an emission at ${\lambda}_{max}$= 430 nm. pH Dependency of fluorescence emission intensity were examined to determine the optimum pH for the fluorophores.

• Bulletin of the Korean Chemical Society
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• v.31 no.11
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• pp.3385-3390
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• 2010

$Li^+$ ion complex of azacrown ether with restricted motion of freedom and pseudo-bilateral symmetry was studied by infrared spectroscopy, which has shown simplified and broadened vibrational features. The C=O and N-H stretching bands, in particular, shows anomalous broadening nearly ${\sim}50\;cm^{-1}$. The density functional calculation at the level of BP86/6-31+$G^{**}$ shows that $Li^+$ ion is trapped and rather free to move around inside the cavity, as much as about $0.70\;{\AA}$. Through the relocation of $Li^+$ ion inside the cavity, the conformational changes would occur rapidly in its symmetry $C_1\;{\rightleftarrows}\;C_2\;{\rightleftarrows}\;C_1$$. The potential barrier was obtained to be merely ~2.2 kJ/mol for $C_1\;{\rightarrow}\;C_2$. During this conformational alteration, the amide backbone twists concurrently its dihedral angle side to side about up to ${\pm}3$ degree. Selected vibrational modes were interpreted in terms of the force constant variations of local symmetry coordinates between conformations in the framework of $C_1\;{\rightleftarrows}\;C_2\;{\rightleftarrows}\;C_1$.

• Bulletin of the Korean Chemical Society
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• v.28 no.5
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• pp.816-820
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• 2007

Novel new red-light emitting perylene fluoroionophore N,N'-dipropyl-1,7-bis(calix[4]azacrown-5-crown-5)- 3,4,9,10-perylene tetracarboxy diimide (3) was prepared by reacting N,N'-dipropyl-1,7-dibromo-3,4,9,10- perylene tetracarboxy diimide (1) with calix[4]azacrown-5-crown-5. Also the alternating copolymer (4) with similar repeating unit was prepared reacting by calix[4]bisazacrown-5 with 1. Metal ion binding by 3 and 4 leads to a blue-shift of absorption band and emission spectra. When ionophoric characteristics were investigated by binding alkali, alkali earth metal and various metal ions, polymeric ionophores displayed large fluorescence decreasing effects with K+, Ag+ and Ba2+, which was rationalized by photo-induced charge transfer (PCT).