Readily prepared iminocoumarin for rapid, colorimetric and ratiometric fluorescent detection of phosgene

In this paper, a new colorimetric and ratiometric fluorescent probe for the rapid detection of phosgene is reported. This probe is based on a readily prepared and highly fluorescent iminocoumarin, which reacts rapidly with phosgene to form a cyclic carbamate product to produce, distinctive colorimetric and ratiometric fluorescent signal changes. The detection of phosgene with this probe is fast (complete within 2 min), highly selective and sensitive with a detection limit of 27 nM in solution. Moreover, this probe can be used to prepare easy-to-use paper test strips for convenient visual and fluorescent detection of phosgene gas even at a concentration of 0.1 mg/L. Overall, this work provides a very promising dual colorimetric and ratiometric fluorescent probe for rapid and sensitive detection of phosgene both in solution and in the gas phase.