Jin Yong Lee

A novel coumarin-based fluorogenic probe bearing the 2-picolyl unit (1) was developed as a fluorescent chemosensor with high selectivity and suitable affinity in biological systems toward Cu(2+) over other cations tested. The fluorescence on-off mechanism was studied by femtosecond time-resolved fluorescence (TRF) upconversion technique and ab initio calculations. The receptor can be applied to the monitoring of Cu(2+) ion in aqueous solution with a pH span 4-10. To confirm the suitability of 1

A major challenge in photodynamic cancer therapy (PDT) is avoiding PDT-induced hypoxia, which can lead to cancer recurrence and progression through activation of various angiogenic factors and significantly reduce treatment outcomes. Reported here is an acetazolamide (AZ)-conjugated BODIPY photosensitizer (AZ-BPS) designed to mitigate the effects of PDT-based hypoxia by combining the benefits of anti-angiogenesis therapy with PDT. AZ-BPS showed specific affinity to aggressive cancer cells (MDA-M

Showing their true colors: Polymers based on polydiacetylene and imidazolium show selective color response to anionic surfactants. Furthermore, this system easily distinguishes between the anionic surfactants sodium dodecyl sulfate (SDS) and sodium dodecylbenzenesulfonic acid (SDBS).

In this study, we developed a turn-on mitochondria-targeting hydrogen sulfide, "probe 1", based on the selective thiolysis of 7-nitro-1,2,3-benzoxadiazole amine moiety attached to the piperazine-based naphthalimide scaffold. Probe 1 exhibited excellent properties with 68-fold fluorescence enhancement, a low detection limit (2.46 μM), a low cytotoxicity, and a good selectivity toward hydrogen sulfide. The success of intracellular imaging indicated that probe 1 could be used in further application

A new sensor for the fluorescent and colorimetric detection of CO(2) is described. The system utilizes fluoride to activate a tetrapropyl benzobisimidazolium salt and operates in the absence of an exogenous base. On the basis of spectroscopic and theoretical analyses, the mode of action of the present system is ascribed to the fluoride-induced formation of an N-heterocyclic carbene intermediate that reacts with CO(2) to form an imidazolium carboxylate.

Recent theoretical studies on geometric and chemical modification strategies, band engineering, and charge carrier dynamics of TiO₂nanoparticles are discussed.

An indole conjugated coumarin 1 for KCN chemodosimeter has been prepared and displayed considerable dual changes in both absorption (blue-shift) and emission (turn-on) bands exclusively for KCN. DFT/TDDFT calculations support that the fluorescence enhancement of 1-KCN is mainly due to blocking of the ICT process.

A new chemodosimetric probe (1) is reported that selectively detects thiols over other relevant biological species by the turning on of its fluorescence through a Michael type reaction. The fluorogenic process upon its reaction was revealed to be mediated by intramolecular charge transfer, as confirmed by time-dependent density functional theory calculations. The application of probe 1 to cells is also examined by confocal microscopy, and its cysteine preference was observed by an ex vivo LC-MS

The recent advances in platinum-free and/or metal-free electrocatalysts for electrochemical redox reactions at the electrodes of fuel cells in particular and, broadly speaking, energy devices were thoroughly reviewed. This comprehensive review focuses on nonplatinum precious metal (Pt-free) and/or nonprecious metal (metal-free) electrocatalysts regarding the electrochemical redox reactions at the electrodes of the energy devices. The recent development of electrocatalysts governing the electroch

A rationally designed, coumarin-based fluorescent sensor imino-coumarin (IC) displays high selectivity for Cu(2+) over a variety of competing metal ions in aqueous solution with a significant fluorescence increase. DFT/TDDFT calculations support that the fluorescence 'turn-on' of IC originates from blocking the electron transfer of the nitrogen lone pair upon complexation with Cu(2+). IC was successfully applied to microscopic imaging for detection of Cu(2+) in LLC-MK2 cells (in vitro) and sever

The design and development of new pyrene-based fluorescent probes, P-Hcy-1 and P-Hcy-2, which display selective fluorescence enhancements in response to homocysteine (Hcy), are described. The distinctly different fluorescence responses of P-Hcy-1 and P-Hcy-2 to Hcy vs. Cys are explained by theoretical calculations. Finally, the results of cell experiments show that these probes can be used to selectively detect Hcy in mammalian cells.

Tiny pores: Benzodifuran moieties were introduced into microporous organic networks (MONs) through a tandem process consisting of Sonogashira coupling of 1,3,5-triethynylbenzene and 2,5-diiodo-1,4-hydroquinone and intramolecular cyclization. The resultant benzodifuran-containing MON showed promising photocatalytic activities in the oxidative conversion of primary amines into imines.

A new naphthalene derivative containing a urea group at the 1,8-position of naphthalene was synthesized and showed a unique absorption and fluorescence peak with fluoride ion. Calculations suggested that a new peak was attributed to the increased anionic character of urea nitrogen due to the strongly charged hydrogen bonding between fluoride and amide protons of the urea. The fluoride selectivity among halides (F(-), Cl(-), Br(-)) comes from the fact that the fluoride approaches much closer to t

A Cu-catalyzed highly Z-stereoselective hydroboration of alkynes with 1,8-naphthalenediaminatoborane (HB(dan)) is developed. DPEphos (bis[(2-diphenylphosphino)phenyl]ether)-ligated Cu catalysts produced alkenylboron compounds from terminal alkynes with excellent Z-stereoselectivity. In contrast, using a SIPr-CuCl complex as the precatalyst exclusively produced E-hydroboration products at mild conditions. Both catalytic procedures form alkenylboron products stereocomplementary to each other, cons