Europium (III) complex-based fluorescent probe for instantaneous, selective, and sensitive detection of phosgene.

[Display omitted] • A europium (III) complex bearing 2-hydroxyl-1H-benzimidazole moiety has been developed as a novel probe toward phosgene. • The probe exhibited giant Stokes shift (248 nm), low detection limit (67 nM) and high selectivity for phosgene sensing in solution. • The probe 1 loaded paper test strips could respond to phosgene gas (0–2 ppm) within 2 min. Phosgene (carbonyl chloride, COCl 2) is a widely used colorless gas in organic synthesis. However, its high toxicity sets a severe potential damage of public safety. As the fluorescence method has the advantages of simple operation and real-time detection of phosgene, it is extremely important to develop a fluorescent phosgene probe for public health and safety. This study aimed to present a simple Eu3+ complex (1) with 2-hydroxyl-1 H -benzimidazole moiety as a novel phosgene probe. Probe 1 exhibited characteristic emission of Eu3+ in CH 3 CN solution, which was specifically quenched after encountering phosgene. The change in the solution color from light red to dark could be easily distinguished with the naked eye under a 365 nm ultraviolet lamp. Finally, the test paper with probe 1 was fabricated for effortless, selective, and visual detection of phosgene gas. [ABSTRACT FROM AUTHOR]