Oxalyl chloride and phosgene are highly toxic chemicals but are widely used in industrial processes, which have been regarded as a serious threat to our health and public security. Thus, it is imperative to develop a convenient and reliable detection method for these noxious agents. In this research, we report the rational design of a fluorescent sensor (denoted as BTA) for simultaneously detecting oxalyl chloride and phosgene, in which o-phenylenediamine (OPD) as the reactive recognition site and benzothiadiazole (BTD) as the fluorophore moiety are coupled into one single benzo-fused motif. The probe works in a “turn-on” fluorescence mode due to the formation of piperazine-2,3-dione and 2-imidazolidinone rings by intramolecular cyclization reactions between the OPD part with oxalyl chloride and phosgene, respectively, which greatly inhibits the intramolecular charge transfer (ICT) process from two amines to the BTD core in the sensor BTA. The detection limit of oxalyl chloride and phosgene is as low as 3 nM and 20 nM in solutions, respectively. Moreover, the sensor exhibits outstanding selectivity toward oxalyl chloride and phosgene over the nerve-agent mimic diethyl chlorophosphate and various acyl chlorides. Furthermore, a portable test paper with BTA has been facilely fabricated for visual on-site detection of the two toxic chemicals in the gas phase.

中文翻译：

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基于苯并噻二唑的荧光传感器，用于选择性检测草酰氯和光气

草酰氯和光气是剧毒化学品，但已广泛用于工业过程，被认为对我们的健康和公共安全构成严重威胁。因此，必须为这些有害物质开发一种方便，可靠的检测方法。在这个研究中，我们报告的荧光传感器（表示为合理设计BTA用于同时检测草酰氯和光气），其中ö-苯二胺（OPD）作为反应性识别位点和苯并噻二唑（BTD）作为荧光团部分偶联到一个单一的苯并稠合基序中。由于OPD部分与草酰氯和光气之间的分子内环化反应形成哌嗪-2,3-二酮和2-咪唑啉酮环，因此该探针以“开启”荧光模式工作，这大大抑制了分子​​内从两种胺到传感器BTA中BTD核的电荷转移（ICT）过程。溶液中草酰氯和光气的检出限分别低至3 nM和20 nM。而且，该传感器对神经药模拟氯仿二乙基二氯和各种酰氯显示出对草酰氯和光气的出色选择性。此外，已经方便地制造了带有BTA的便携式试纸，用于目测现场检测气相中的两种有毒化学物质。