A coumarin–dihydroperimidine dye as a fluorescent chemosensor for hypochlorite in 99% water |
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Authors: | Yasuhiro Shiraishi Chiharu Yamada Takayuki Hirai |
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Affiliation: | Research Center for Solar Energy Chemistry, Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, Toyonaka 560-8531 Japan, |
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Abstract: | The hypochlorite anion (OCl−), a reactive oxygen species (ROS), is an important microbicidal agent in the immune system. Accurate and selective detection of OCl− in environmental and biological samples by a fluorescent molecular sensor is an important subject. All previously reported sensors, however, have suffered from tedious multi-step synthesis for the sensors and the use of large amounts of organic solvents for the analysis. Herein, we report that a coumarin–dihydroperimidine dye prepared by facile condensation behaves as a fluorescent sensor for OCl− in 99% water. The sensor exhibits weak fluorescence, but OCl−-selective dehydrogenation of its dihydroperimidine unit creates a strong blue fluorescence. This turn-on fluorescence response facilitates selective and sensitive detection of OCl− in the physiological pH range. Ab initio calculation revealed that the fluorescence enhancement by OCl− is triggered by intramolecular proton transfer from the coumarin –OH to the imine nitrogen of the formed perimidine moiety.A coumarin–dihydroperimidine dye exhibits strong blue fluorescence by OCl−-selective dehydrogenation of the dihydroperimidine unit, and facilitates selective and sensitive fluorometric detection of OCl− in 99% water. |
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