An amino-substituted 2-(2′-hydroxyphenyl)benzimidazole for the fluorescent detection of phosgene based on an ESIPT mechanism

In this work, an ESIPT-based fluorescence probe, 5′-amino-2-(2′-hydroxyphenyl)benzimidazole ( P1 ), was synthesized and explored for the ratiometric detection of phosgene. Compared to 2-(2′-hydroxyphenyl)benzimidazole (HBI), P1 exhibits high sensitivity (LoD = 5.3 nM) and selectivity toward phosgene with the introduction of the amine group. Furthermore, simple P1 loaded test papers are manufactured and display selective fluorescent detection of phosgene in the gas phase. An easily prepared phosgene probe, 5′-amino-2-(2′-hydroxyphenyl)benzimidazole ( P1 ), is designed and studied. Based on ESIPT mechanism, P1 exhibits ratiometric, sensitive and selective detection of phosgene both in solution and gas phase.