BODIPY-based fluorescent chemosensor for phosgene detection: confocal imaging of nasal mucosa and lung samples from mouse exposed to phosgene.

The improper use of phosgene, either as a chemical warfare agent or a leak during chemical production, causes significant risks to human life and property. Therefore, it is particularly important to develop a rapid and highly selective method for the detection of phosgene. In this article, a highly selective fluorescent sensor ONB with a BODIPY unit as a fluorophore and o-aminophenol as a reactive site was constructed for the selective and rapid detection of phosgene in solution. The ONB-containing nanofibers were sprayed onto a non-woven fabric by electrostatic spinning and cut into test films, which can be used well for the detection of gaseous phosgene. While, there were no reported bio-imaging applications for phosgene detection. In this work, nasal mucosa and lung samples from the mice exposed to gaseous phosgene after dropping the ONB solution through the nasal cavity achieved bio-imaging applications successfully.

Rapid and Effective Reaction of 2-Methylpyridin-N-oxides with Triphosgene via a [3,3]-Sigmatropic Rearrangement: Mechanism and Applications.

A facile and effective synthesis of 2-chloromethylpyridines was developed by a one-pot reaction of 2-alkylpyridin-N-oxides and triphosgene at room temperature. As starting materials, N-oxides of 2-alkylpyridine derivatives, including 2-alkylpyridines, 2-methyl quinolines, and phenanthroline, can react rapidly with triphosgene in the presence of triethylamine, affording 2-chloromethylpyridines in good to excellent yields (52-95%). Using the 2-methylquinoline substrate for the mechanistic study, it has been well demonstrated that the chlorination reaction undergoes a [3,3]-sigmatropic rearrangement, which can be observed as a reversible process by monitoring the intermediates. Moreover, the chlorination reaction can be used to construct a rapid and sensitive fluorescent probe for the detection of phosgene.

BODIPY-Based Fluorescent Sensor for the Recognization of Phosgene in Solutions and in Gas Phase.

As a highly toxic and widely used chemical, phosgene has become a serious threat to humankind and public security because of its potential use by terrorists and unexpected release during industrial accidents. For this reason, it is an urgent need to develop facile, fast, and selective detection methods of phosgene. In this Article, we have constructed a highly selective fluorescent sensor o-Pab for phosgene with a BODIPY unit as a fluorophore and o-phenylenediamine as a reactive site. The sensor o-Pab exhibits rapid response (∼15 s) in both colorimetric and turn-on fluorescence modes, high selectivity for phosgene over nerve agent mimics and various acyl chlorides and a low detection limit (2.7 nM) in solutions. In contrast to most undistinguishable sensors reported, o-Pab can react with phosgene but not with its substitutes, triphosgene and biphosgene. The excellent discrimination of o-Pab has been demonstrated to be due to the difference in highly reactive and bifunctional phosgene relative to its substitutes. Furthermore, a facile testing paper has been fabricated with poly(ethylene oxide) immobilizing o-Pab on a filter paper for real-time selective monitoring of phosgene in gaseous phase.

Phenothiazine-based fluorescent probes for the detection of hydrazine in environment and living cells.

As an important chemical raw material, hydrazine brings convenience to people's lives and provides opportunities for human development. However, the misuse or leakage of hydrazine has brought pollution to the environment, including water, soil and living organisms. At the same time, hydrazine poses a potential threat to human health as a carcinogen. Despite the enormous challenges, it is crucial to develop an effective method to detect hydrazine in environmental samples. In this work, we have synthesized a series of probes based on phenothiazine fluorophore by the introduction of different substituents and developed a novel probe for the detection of hydrazine. The probe is capable of detecting hydrazine in aqueous solutions with high sensitivity and selectivity, and can be easily fabricated into paper test strips for use in in situ samples. In addition, the probe is effective in detecting hydrazine in water, soil, cells, and zebrafish, providing an excellent tool for detecting hydrazine in the environment.

Phenothiazine and semi-cyanine based colorimetric and fluorescent probes for detection of sulfites in solutions and in living cells.

Four hemicyanine probes for selectively detecting sulfites (HSO3 -/SO3 2-) have been constructed by the condensation reaction of 7-substituted (CN, Br, H and OH) phenothiazine aldehyde with 1-ethyl-2,3,3-trimethylindolium iodide. All four probes show a fast and sensitive response to HSO3 -/SO3 2- via a Michael addition, with a detection limit lower than 40 nM based on monitoring their UV/vis absorption changes. Although all four probes display an increase in fluorescence when responding to HSO3 -/SO3 2-, the increment is larger for the probe with an electron-withdrawing group than the probe with an electron-donating group, except for Br. Thus, among four probes the 7-cyano probe (PI-CN) possesses the largest fluorescent response to HSO3 -/SO3 2-, and the lowest detection limit (7.5 nM). More expediently and easily, a film and a test paper with PI-CN have been prepared to detect HSO3 -/SO3 2- in a sample aqueous solution selectively. Finally, the detection of HSO3 -/SO3 2- by PI-CN in biological environments has been demonstrated by cell imaging.

Two-Step Sensing, Colorimetric and Ratiometric Fluorescent Probe for Rapid Detection of Bisulfite in Aqueous Solutions and in Living Cells.

Bisulfite and sulfite (HSO3 -/SO3 2-) are not only widely used toxic chemicals but also active anions with important biological functions. Hence, the development of new detection methods for HSO3 -/SO3 2- is important for environmental security and human health. In this paper, we report a symmetrical hemicyanine for the detection of HSO3 -/SO3 2-, SHC, which is constructed with p-diphthalaldehyde with trimethylbenzoindolium via condensation. The red fluorescent probe can fast respond to HSO3 -/SO3 2- (<30 s) to give cyan fluorescence, and its sensing process is twice nucleophilic additions, which were observed from fluorescence response, initial ratiometric change, and subsequent turn-on increment; especially in a low-concentration level, the ratiometric fluorescence measurement can eliminate environmental interference. This probe can achieve a quantitative detection of HSO3 -/SO3 2- in a wide concentration range. Furthermore, the probe SHC is a mitochondria-specific probe for ratiometric fluorescent detection of HSO3 -/SO3 2- in living cells.

Fluorescent Chemosensor for Selective Detection of Phosgene in Solutions and in Gas Phase.

The detection of highly toxic chemicals in a convenient, fast, and reliable manner is essential for coping with serious threats to humankind and public security caused by unexpected terrorist attacks and industrial accidents. In this paper, a highly selective fluorescent probe has been constructed through o-phenylenediamine covalently linking to coumarin (o-Pac), which can respond to phosgene in turn-on fluorescence mode. The response time is less than 0.5 min and the detection limit is as low as 3 nM in solutions. More importantly, the sensor exhibits good selectivity to phosgene over triphosgene and various acyl chlorides. Furthermore, a portable test paper has been fabricated with polystyrene membrane containing o-Pac for real-time selective monitoring of phosgene in gas phase.