Synthesis of Oxadiazolones with Hydrazides: The Mechanism and the Sensing Application as Sensitive, Rapid, and Visual Fluorescent Sensors for Phosgene.

The reaction of hydrazides with triphosgene in the presence of triethylamine is a facile method to construct various oxadiazolones. Utilizing this reaction, a new class of colorimetric and fluorogenic phosgene chemosensors were developed with the BODIPY as fluorophore, five BODIPY-based hydrazides, which exhibited highly effective reactions with phosgene. The mechanism was updated. Finally, the test paper with a hydrazide was fabricated for facile, selective, and visual detection of phosgene gas.