A coumarin-dihydroperimidine dye as a fluorescent chemosensor for hypochlorite in 99% water

• Published in: RSC advances Vol. 9; no. 49; pp. 28636 - 28641
• Main Authors: Shiraishi, Yasuhiro, Yamada, Chiharu, Hirai, Takayuki
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 11.09.2019; The Royal Society of Chemistry
• Subjects: Biological properties; Cartesian coordinates; Chemical sensors; Chemistry; Chemoreceptors; Coumarin; Dehydrogenation; Dyes; Fluorescence; hypochlorites; imines; immune system; moieties; nitrogen; reactive oxygen species; Sensors; solvents
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/c9ra05533a

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.