Rapid, specific, and ultrasensitive fluorogenic sensing of phosgene through an enhanced PeT mechanism

We report the design of an enhanced PeT-based fluorogenic phosgene probe 1-CN comprising a BODIPY fluorescence reporter, and a catechol quencher at the meso-position acting as the phosgene reaction site. The fluorescent catechol-derived probe 1-CN specifically reacts with phosgene to result in a cyclic carbonate ester. The fast (< 3 s) reaction suppresses a reductive PeT quenching process, leading to a fluorescence turn-on signal (F/F0 up to ca. 1300). The high sensitivity (LOD = 24 pM) of the probe is achieved by the precise adjustment of the energy levels of the frontier orbitals involved in the PeT.