Rational design of fluorescent phosgene sensors.

Phosgene is a very toxic gas, which was used as a chemical weapon in World War I, and is currently widely used in industrial processes. So far, no any phosgene fluorescent sensor has been reported. In this study, we report rational design of unimolecular fluorescent phosgene sensors for the first time. Phosgene was used to initiate intramolecular cyclization and convert nonfluorescent molecules to highly fluorescent products. Bright blue fluorescence of phosgene reaction products can be easily visualized by naked eye. The detection limit for phosgene is as low as 1 nM in solutions at room temperature.