Publications by authors named "Chi-Hwa Lee"

Light-driven Au(III)-promoted oxidative cleavage of triazole-bearing amine derivatives is utilized for the detection of ionic gold in aqueous media. A bistriazole-bearing boron dipyrromethane (1(BODIPY)) exhibited selective and sensitive fluorescence enhancement by the addition of Au(3+) and subsequent UV irradiation.

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A bisindole-bridged-porphyrin tweezer (1), a pair of zinc porphyrins (PZn's) connected to bisindole bridge (BB) via the Cu(I)-mediated alkyne-azide click chemistry, exhibited unique switching in forward and backward photoinduced energy transfer by specific guest bindings. The addition of Cu(2+) caused a change in electronic absorption and fluorescence quenching of 1. MALDI-TOF-MS and FT-IR analyses indicated the formation of stable coordination complex between 1 and Cu(2+) (1-Cu(II)).

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A new type of molecular tweezer (1) has been synthesized for the direct determination of the absolute configuration of chiral carboxylates without analyte derivatization. Upon the addition of diamine and anionic guests, 1 exhibited shifts in its absorption spectrum with clear isosbestic points. The continuous variation method indicated that both the diamine and anionic guests form 1:1 host-guest complexes with 1 with very high binding affinity.

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A new type of porphyrin ligand bearing four triazole groups at the ortho-positions of phenyl rings in tetraphenylporphyrin was synthesized for the formation of monoporphyrinate lanthanide complexes without ancillary ligands.

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A zinc porphyrin-based receptor containing four triazole groups at the ortho-position of each phenyl group (1) was utilized as a useful probe for the determination of contaminants in acetonitrile (MeCN). Through the simple observation of the absorption spectrum of 1 in MeCN, the cyanide contamination concentration could be directly determined.

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Red means CN: A new type of diketopyrrolopyrrole-based chromophore has been synthesized as a colorimetric and fluorescent probe for the detection of cyanide using only two reaction steps. Through the addition of cyanide to the chromophore, the fluorescence emission and color were greatly changed in a highly sensitive and selective manner.

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Turn on events: A molecular probe consisting of a boradiazaindacene unit conjugated with a dicyano-vinyl group has been designed for the selective and sensitive detection of cyanide by strong fluorescence enhancement in aqueous media (see scheme).

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A new type of host compound (1), tetraphenyl zinc-porphyrin (ZnTPP) that contains four triazole groups at the ortho-position of each phenyl group, has been synthesized and characterized by using (1)H, (13)C NMR, and MALDI-TOF-MS analyses. The host-guest complex formation between 1 and halides was investigated by using (1)H NMR spectroscopy in [D(6)]DMSO. The triazole, benzyl, and phenylene proton signals were shifted upfield by the addition of halides in the form of tetrabutylammonium salts, which implies that the triazole protons in 1 are allocated very closely to the porphyrin ring and are directed toward the binding pocket over the porphyrin ring during the formation of hydrogen bonds.

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A new type of fluorescent probe (1) with two triazole groups that are conjugated with a carbazole moiety was synthesized by a Cu(I)-catalyzed alkyne-azide click reaction for the selective and sensitive detection of cyanide via fluorescence enhancement by ligand exchange and metal ion removal.

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A macrocyclic host, a pair of zinc porphyrins bridged by two anion-acceptable indolocarbazole moieties, has shown strong positive homotropic allosterism upon anionic guest bindings with an inhibitory control mechanism by DABCO addition.

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A cyclodipeptide-bridged porphyrin dimer has formed fibrous and toroidal multi-porphyrin array systems by hydrogen bonding-mediated self-assembly.

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