A highly selective phenothiazine-based fluorescent chemosensor for phosgene

A fluorescent chemosensor was developed for selective detection of phosgene, which was comprised of a 2-hydroxyl phenothiazine skeleton and 1H-phenanthro[9,10-d]imidazolyl moiety. The chemosensor displayed a high selectivity toward phosgene over other reactive analytes because the adjacent phenolic hydroxyl and imidazolyl synergistically construct a bi-functional reaction site for phosgene with bi-acyl chloride structure. The fluorescence intensity of the chemosensor at 492 nm was apparently enhanced upon reaction with phosgene, and the chemosensor-loaded polymeric film was successfully applied in monitoring phosgene vapor by obvious fluorescence changes.