Browsing by Author "Kang, Jongmin"

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A dihydrogen phosphate selective anion receptor based on acylhydrazone and pyrazole
(2015-01-01)
Pandian, Thiravidamani Senthil
;
Choi, Yusun
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Srinivasadesikan, Venkatesan
;
Lin, Ming-Chang
;
Kang, Jongmin
A novel chromogenic anion receptor 1 based on acylhydrazone and pyrazole has been designed and synthesized. Chromogenic anion receptor 1 forms stable 1:1 complexes with dihydrogen phosphate (H2PO4-) and other halide (Cl-, Br-) anions in DMSO solution, as shown by UV-vis, fluorescence and H-1 NMR spectroscopic experiments. The pyrazole containing host 1 in the optimized geometry of the complex has been noted as planar. The planarity of the host with the H2PO4- anion resulted from four strong N-H center dot center dot center dot O and two weak C-H center dot center dot center dot O types of H-bonding. In total six H-bonding and the planarity of the host in the complex are responsible for the high binding energy. The addition of an excess of more basic anions (F- and CH3COO-) induces stepwise deprotonation, an event signalled by the appearance of a bright yellow color. The intensity of the fluorescence spectrum increases when hydrogen bonding occurs and decreases when deprotonation occurs, which is evidenced by fluorescence titrations.
A Hydrogen Pyrophosphate Selective Anion Receptor Based on Thiosemicarbazone
(2017-12-01)
Pandian, Thiravidamani Senthil
;
Srinivasadesikan, Venkatesan
;
Lin, Ming-Chang
;
Park, Jong I. L.
;
Kang, Jongmin
A novel rigid anion receptor 1 containing thiosemicarbazone groups were synthesized. Receptor 1 displayed competitive turn-off fluorescence and colorimetric response for hydrogen pyrophosphate. This recognition process was confirmed by UV-vis, fluorescence titrations. A detailed analysis of the TD-density functional theory calculations was consistent with the observed colorimetric experiments. These experiments revealed that the colorimetric and fluorescent response is triggered by thiourea/ HP2O73- hydrogen bonding.
A selective acetate anion binding receptor: participation via cationic CH3 donors
(2015-10-28)
Pandian, Thiravidamani Senthil
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Srinivasadesikan, Venkatesan
;
Lin, M. C.
;
Kang, Jongmin
;
應用化學系
A novel receptor 1, which has only C-H hydrogen bonds as recognition element has been designed and synthesized. The receptor 1 utilizes cationic CH3 in 2-methyl benzimidazole and naphthalene benzylic C-H as hydrogen bonding donor. The binding cavity formed in receptor 1 prefers to accommodate small negatively charged atom such as oxygen. Therefore, acetate and nitrite show strong affinity for receptor 1 in acetonitrile due to negatively charged oxygen in them. In addition, the order of binding affinity for halides are Br->Cl->I-. These results reflect the size and basicities of halides. Further, H-1 NMR titration of halide clearly indicates the anion-pi interaction. The experimental data from UV-vis, fluorescence and 1H NMR titration are consistent with DFT results. (C) 2015 Elsevier Ltd. All rights reserved.
Anion receptors based on 4-nitrophenylhydrazone
(2016-07-20)
Jo, Jaeyoung
;
Putikam, Raghunath
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Lin, M. C.
;
Kang, Jongmin
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應用化學系
We have designed and synthesized new chromogenic anion receptors 1 and 2, which utilized 4-nitrophenylhydrazone as anion recognition moiety. UV-vis and H-1 NMR titration showed that receptors 1 and 2 bound anions utilizing two hydrazone N-H hydrogen bond and two C-H hydrogen bond. Despite the weak hydrogen bonding abilities of binding motifs, receptor 1 showed affinities for dihydrogen phosphate and acetate and receptor 2 showed relatively strong affinities for dihydrogen phosphate in polar solvent such as 5% DMSO in CH3CN. (C) 2016 Elsevier Ltd. All rights reserved.
Nitrite selective anion receptor based on 1-methyl-1H-perimidine
(2015-10-07)
Pandian, Thiravidamani Senthil
;
Srinivasadesikan, Venkatesan
;
Lin, M. C.
;
Kang, Jongmin
;
應用化學系
A new anion receptor 1, which utilizes only C-H hydrogen bonding have been designed and synthesized. This receptor utilizes both aromatic C-H (two perimidine C2-H, anthracene 9-H) and aliphatic C-H (two perimidine 1-methyl C-H, two benzylic C-H) as hydrogen bonding moieties. The receptor 1 is found to have considerable binding affinity for weakly basic anions even in polar solvent such as DMSO. In addition, receptor 1 is selective for nitrite. The experimental data from UV-vis, fluorescence and H-1 NMR titration are consistent with theoretical studies. The order of the interaction of the C-H groups of perimidine containing receptor with NO2- anion is found to be perimidine (C-H)>methylene (C-H)>methyl (C-H)>anthracene (C-H). 0 2015 Elsevier Ltd. All rights reserved.