Hyun Yong Jo

A single chemosensor for multiple analytes: fluorogenic detection of Zn2+ and OAc− ions in aqueous solution, and an application to bioimaging

A new highly selective and sensitive chemosensor 1 for both Zn2+ and OAc− with off–on fluorescence behavior in aqueous solution was developed. The selectivity mechanism of 1 for zinc is based on a combinational effect of the inhibition of excited-state intramolecular proton transfer and CN isomerization, and chelation-enhanced fluorescence. As a practical application, in vitro studies with fibroblasts showed fluorescence in the presence of both the receptor 1 and Zn2+. Moreover, the deprotonated 1 can behave as a chemosensing system for turn-on detection of OAc− in preference over various other anions tested. Therefore, 1 can serve as ‘one sensor for multiple analytes’.

A colorimetric chemosensor based on a Schiff base for highly selective sensing of cyanide in aqueous solution: the influence of solvents

A new highly selective colorimetric chemosensor 1 (E)-9-(((2-hydroxy-5-nitrophenyl)imino)methyl)-2,3,6,7-tetrahydro-1H,5H-pyrido[3,2,1-ij]quinolin-8-ol for CN− was developed. Receptor 1 showed exclusive response toward cyanide by a color change in aqueous solution. However, in aprotic solvents and methanol, the unique selectivity of 1 for CN− disappeared, and its nonselective color change was observed for other anions. This phenomenon could be possibly explained by the combination of the basicity and the hydrogen bonding ability of the anions. Moreover, 1 could be used as a practical, visible colorimetric test kit in an aqueous environment.

A new coumarin-based chromogenic chemosensor for the detection of dual analytes Al3+ and F−

A multifunctional colorimetric receptor 1 (2-(3-nitro-2-oxo-2H-chromen-4-ylamino)-3-aminomaleonitrile) for the detection of both Al3+ and F− has been developed. The receptor 1 showed a significant color change in the presence of Al3+ over most other competitive metal ions including Ga3+ and In3+ in aqueous solution. The selectivity mechanism of 1 for Al3+ might be attributed to the enhancement of the intramolecular charge transfer band. Interestingly, it could be recycled simply through treatment with an appropriate reagent such as ethylenediaminetetraacedtic acid. Moreover, 1 showed a highly selective colorimetric response to F− due to the decrease in the intramolecular charge transfer band by a deprotonation process without any interference from other anions. Therefore, 1 can serve as a ‘single sensor for dual targets’.