A simple AIE-based indole-benzimidazole probe for the ratiometric fluorescent detection of phosgene in an almost neat...

Phosgene is a suffocating toxic gas that seriously threatens human health and public security. With this research, we developed a simple ratiometric fluorescent probe (1) bearing indole and benzimidazole moieties as the sensing sites and employed it for the aggregation-induced emission-based (AIE-based) detection of phosgene. It was the first time that the probe could detect phosgene in an almost pure aqueous solution (f_w = 99.5 %). Probe 1 had AIE-activity, and the maximum emission peak was 392 nm with increasing water fraction (0-99.5 %). When reacting with phosgene, the emission peak at 392 nm gradually decreased, while a new peak appeared at 449 nm and continued to increase with increasing water fraction (0-99.5 %). Probe 1 exhibited a rapid response toward aqueous phosgene with high selectivity and sensitivity (limit of detection being 23.8 nM). Additionally, we fabricated 1-loaded test strips for gas phosgene detection, enabling dual-channel detection under 245 nm and 365 nm hand-held UV lamps. Finally, this probe was used to monitor phosgene in bionic samples.