Sensitive and Visual Detection of Phosgene by a TICT‐Based BODIPY Dye with 8‐(o‐Hydroxy)aniline as the Active Site

Abstract

Phosgene and its substitutes (diphosgene and triphosgene) are widely utilized as chemical industrial materials and chemical warfare agents and pose a threat to public health and environmental safety due to their extreme toxicity. Research efforts have been directed to develop selective and sensitive detection methods for phosgene and its substitutes. In this paper, we have prepared two BODIPY‐based fluorescent probes, o‐Pah and o‐Pha, which are two isomers with different active sites, ortho‐aminohydroxy (3′,4′ or 4′,3′) phenyls at meso position of BODIPY, and compared their sensing performance toward triphosgene. The probe with o‐(4′‐amino‐3′‐hydroxyl), o‐Pha, exhibits better sensing performance over the o‐(3′‐amino‐4′‐hydroxyl), o‐Pah, for instance, a lower limit of detection (LOD) (0.34 nm vs. 1.2 nm), and more rapid response (10 s vs. 200 s). Furthermore, based on the above comparative studies, a red‐fluorescence probe o‐Phae has been constructed through extending 3,5‐conjugation of o‐Pha. The probe o‐Phae displays rapid response (60 s), high sensitivity to triphosgene (LOD=0.88 nm), and high selectivity for triphosgene over relevant analytes including nitric oxide. Finally, a facile test strip for phosgene was fabricated by immobilizing o‐Phae in a polyethylene oxide membrane for sensitive (<2 ppm) and selective detection of phosgene in the gas phase.

A coumarin-pyrazole-based probe for the fluorescence detection of phosgene with high selectivity and sensitivity

“…7 Many successful phosgene probes have already been reported due to the extreme electrophilicity of the carbon atom in phosgene. 8 The most common strategy relies on two nucleophilic recognition sites, 9 such as ophenylenediamine, [10][11][12] ethylenediamine, 6,13 ethanolamine, 14 3-1H-imidazole-iminecoumarin 15 or 2-hydroxyl/aminophenyl-1Himidazole 8,16 to be simultaneously acylated by phosgene. This process regulates the effect of photoinduced electron transfer (PET), internal charge transfer (ICT), or excited state intramolecular photon transfer (ESIPT), causing uorescence spectral changes.…”

A Rapid, Highly Sensitive and Selective Phosgene Sensor Based on 5,6‐Pinenepyridine

“…The main colorimetric and fluorescent sensing reactions for phosgene detection are using 1,2‐diamine type compounds in which the acylation of one amino group by phosgene and subsequent intramolecular nucleophilic attack of the second amino group lead to the formation of cyclic urea‐derivatives, resulting in an off‐on response (Scheme 1 ). [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ] The fluorophores are usually BODIPY,[ 20 , 21 , 22 , 23 , 24 ] coumarins,[ 25 , 26 ] 1,8‐naphthalimide,[ 17 , 27 , 28 ] anthracene carboxyimide,[ 29 , 30 , 31 ] 2‐(2’‐hydroxyphenyl)benzothiazole (HBT) [32] or rhodamine. [12] The response rates and sensitivity of these sensors are very diverse and can be significantly slowed down due to the inactivation of the second amino group once the first one undergoes electrophilic attack from the phosgene.…”

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

“…Nowadays, fluorescent detection methods are well developed and widespread due to their easy manipulation, fast response, high sensitivity and selectivity, and the possibility of real-time detection. Among them, reports on the fluorescent detection of phosgene are still limited 12–14 and mainly based on: (i) twice carbamylation reactions of fluorescence probes, which employ o -phenylenediamine, 21 o -hydroxyaniline, 22 o -aminobenzyl amine, 23 catechol, 24 ethylenediamine, 25 ethanolamine 26 or other moieties 27 as reactive site; (ii) phosgene-promoted dehydration reaction of fluorescence probes, which employ oxime 28 or amide 29 as reactive site; and (iii) several other phosgene-induced reactions, including intermolecular reaction of two fluorophores, 30 intramolecular reaction of cinnamic acids, 31 ring opening reaction of benzimidazole-fused rhodamine dye 32 and Beckmann rearrangement of ketoxime 33 (Table S2 † ). However, most of these fluorescence probes are based on mechanisms of photoinduced electron transfer (PeT), intramolecular charge transfer (ICT) or aggregation-induced emission (AIE), which might be disturbed by acetylating, 21 c phosphorylating agents 21 h or oxidizing chemicals, 21 e ,27 g resulting to false response.…”

“…And several other drawbacks still need to be overcome, such as incapable of discrimination between triphosgene and phosgene 21 b ,21 f and tedious preparation process. 22,24,25 …”