Eun Jin Jun

A Benzobisimidazolium-Based Fluorescent and Colorimetric Chemosensor for CO2

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.

One-photon and two-photon sensing of biothiols using a bis-pyrene-Cu(II) ensemble and its application to image GSH in the cells and tissues.

Glutathione (GSH), cysteine (Cys), and homocysteine (Hcy) are three major biothiols, which play key roles in various biological systems. Accordingly, the development of imaging probes has been actively studied. We report a new pyrene derivative 1, which showed large fluorescence quenching with Cu(2+) at pH 7.4. The ensemble 1-Cu(2+) was applied to detect biothiols. Among the various amino acids, GSH, Cys, and Hcy induced distinct turn-on fluorescence changes. The 1-Cu(2+) ensemble was further applied for GSH detection in living cells.

Cyclic benzobisimidazolium derivative for the selective fluorescent recognition of HSO4−via a combination of C–H hydrogen bonds and charge interactions

In this study, a novel fluorescent cyclic benzobisimidazolium derivative was designed and prepared for the selective recognition of HSO4−. Pre-organization, neutral C–H hydrogen bonds and charge interactions play key roles in recognizing HSO4− in aqueous solution. Spectroscopic studies, including UV-vis and fluorescence, showed that this cyclic receptor exhibited high selectivity in response to HSO4−. X-Ray crystal data, NMR data and theoretical calculations are presented to explain its unique binding mode.

Recognition of myo-inositol 1,4,5-trisphosphate using a fluorescent imidazolium receptor

The first example of an imidazolium-based fluorescent receptor for D-myo-inositol 1,4,5-trisphosphate (IP(3)) is reported in this study. The fluorescent receptor 1 bearing four imidazolium and pyrene groups displayed a large fluorescent quenching effect with myo-IP(3) compared to fluorescent changes with various IP series, pyrophosphate, and ATP.

Selective Recognition of Fluoride by using a Benzobisimidazolium Derivative through Aggregation‐Induced Fluorescence

Abstract A new benzobisimidazolium derivative (1) bearing four naphthalene moieties was synthesized and demonstrated as an F− ion‐selective fluorescent chemosensor. The fluorescence of 1 in acetonitrile (CH3CN) is significantly stronger with F− and acetate (CH3CO2 −), but not with other anions (Cl−, Br−, I−, HSO4 −, and H2PO4 −). The fluorescence of 1 is enhanced selectively with F− in the presence of a small amount of water. Our DFT calculations indicate that the electrostatic interactions between the positively charged benzobisimidazolium moieties and F− play an important role in the formation of stable aggregates. The formation of stable aggregates of 1 with F− in CH3CN is a key step for the selective sensing of F−, and the fluorescence of the aggregates is further enhanced in a mixture of 95 % CH3CN and 5 % water, which can be attributed to the aggregation‐induced emission.