Sensitive and Selective Detection of Phosgene, Diphosgene, and Triphosgene by a 3,4‐Diaminonaphthalimide in Solutions and the Gas Phase

Abstract

Phosgene and its substitutes, diphosgene and triphosgene, are highly toxic and widely used chemicals, so it is necessary to investigate their reactivity and develop facile, sensitive, and specific methods for detecting them. In this work, we have developed a new 1,8-naphthalimide-based fluorescent chemosensor, Phos-2, which exhibits high sensitivity (detection limits: 0.2-0.7 nm), high selectivity to phosgene and its substitutes over nitric oxide (NO), various acyl chlorides, and nerve agent mimics in solutions. Based on investigation of the reaction kinetics of Phos-2 with phosgene and its substitutes, a two-step sensing mechanism was clarified. The second-order rate constants (k ) of Phos-2 reveal that the relative rate constants of phosgene, diphosgene, and triphosgene are 40:4:1. Moreover, a Phos-2 test paper has been fabricated as a low-cost, sensitive (≈5 ppm from observation by the naked eye or 0.1 ppm from a measurement), and efficient method for visual detection of a low concentration of phosgene in the gas phase.

Spectral Characteristic of Phosgene in External Electric Field

“…In 2021, Patrick Vossnacker's team searched for new synthesis methods of phosgene [10] ; however, it is found susceptible to hydrolysis, which generates chlorine free radicals that have a destructive chain reaction with the ozone layer (Cl + O3 → ClO + O, ClO + O3 → Cl + 2O2) [11] . At present, the research on phosgene mainly includes phosgene toxicity [12,13] , treatment methods after phosgene poisoning [14,15] , and more on the detection methods of phosgene [16][17][18] . Scholars have neglected the harm caused by phosgene when in use; therefore, the problem of phosgene degradation needs to be solved urgently.…”

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

“…Due to their low cost, specificity, high sensitivity, and ease of use, many fluorescent probes for phosgene have been reported [5] with two nucleophilic groups as the active site for the reaction, o ‐diamine (including one amine plus one o ‐aromatic nitrogen), [6a–y] one amine plus one o ‐hydroxy group, [7a–c] o ‐dihydroxy [8] group and others, [9a–l] and summarized in Table S1 in the Supporting Information. Among the largest class of probes, with o ‐phenylenediamine as the active site, would produce a similar fluorescence response to nitric oxide (NO), [6e, f] which induces o ‐phenylenediamine to form benzotriazole [10] …”

Selectively Light-up Detection of Phosgene with an Aggregation-Induced Emission-Based Fluorescent Sensor

“…In contrast, fluorescence-based sensing systems are strikingly advantageous because of their low cost, high sensitivity, simple operation, and great convenience for field detection . Over the past years, a variety of fluorescent sensors for phosgene have been developed by utilizing different fluorophores, such as BODIYs, − coumarins, , rhodamines, , naphthalimides, − and others. − In general, the molecular design strategy mainly depends on phosgene-mediated reactions with electron-donating amine or hydroxyl groups in these sensors, resulting in the generation of electron-withdrawing carbamate, urea, or nitrile. These specific transformations typically lead to the suppression of fluorescence quenching processes, including photoinduced electron transfer (PET), − ,, intramolecular charge transfer (ICT), ,,− , or excited state intramolecular proton transfer (ESIPT). , Additionally, other sensing reactions mediated by phosgene involve the ring-opening of amino-containing spiro-(deoxy)­lactam, cyclization of hydroxyl cinnamic acids, and hetero-cross-linking of amino-containing acceptor and donor fluorophores to give a FRET process …”

“…Over the past years, a variety of fluorescent sensors for phosgene have been developed by utilizing different fluorophores, such as BODIYs, − coumarins, , rhodamines, , naphthalimides, − and others. − In general, the molecular design strategy mainly depends on phosgene-mediated reactions with electron-donating amine or hydroxyl groups in these sensors, resulting in the generation of electron-withdrawing carbamate, urea, or nitrile. These specific transformations typically lead to the suppression of fluorescence quenching processes, including photoinduced electron transfer (PET), − ,, intramolecular charge transfer (ICT), ,,− , or excited state intramolecular proton transfer (ESIPT). , Additionally, other sensing reactions mediated by phosgene involve the ring-opening of amino-containing spiro-(deoxy)­lactam, cyclization of hydroxyl cinnamic acids, and hetero-cross-linking of amino-containing acceptor and donor fluorophores to give a FRET process …”