Sen Bhaskar, Patra Sumit Kumar, Khatua Snehadrinarayan
Centre for Advanced Studies, Department of Chemistry, North-Eastern Hill University, Shillong, Meghalaya 793022, India.
Inorg Chem. 2021 Dec 20;60(24):19175-19188. doi: 10.1021/acs.inorgchem.1c02987. Epub 2021 Dec 7.
A bis-heteroleptic ruthenium(II) complex, , of 4,7-bis(2-aminoethylamino)-1,10-phenanthroline for selective "turn-on" detection of highly toxic chemical warfare agent phosgene is presented. Probe exhibits aggregation-induced emission (AIE), and the restricted intramolecular motion is responsible for the AIE activity. In a CHCl/CHCN [95:5 (v/v)] solvent mixture, a unique self-assembled vesicular structure was formed after aggregation, which was supported by transmission electron microscopy, field emission scanning electron microscopy, and atmoic force microscopy studies. Probe showed a rapid and highly selective luminescence turn-on response for phosgene over other competitive chemical warfare agents with a low detection limit (13.9 nM) in CHCN. The 2-aminoethylamino groups in act as a reacting site for nucleophilic addition to the carbonyl center of phosgene and undergo intramolecular cyclization. The final product of the phosgene-mediated reaction, , contains 2-imidazolidinone groups, which has been confirmed by electrospray ionization mass spectometry and H nuclear magnetic resonance (NMR) spectroscopy. H NMR titration of with phosgene supported the reaction mechanism and also pointed to the simultaneous reaction of phosgene at two 2-aminoethylamino sites. For the first time, the crystal structure of the phosgene reaction product, , containing the cyclized 2-imidazolidinone group was confirmed by single-crystal X-ray diffraction, which indubitably validates the reaction mechanism. Triplet state time-dependent density functional theory calculations showed that the weak luminescence of was mostly due to the population of the non-emissive MC state. The cyclization reaction with phosgene and the corresponding 2-imidazolidinone product formation populated the emissive MLCT state in and is the key reason for the enhanced luminescence. Furthermore, a low-cost portable test paper strip has been fabricated with for the real-time selective monitoring of phosgene gas at the nanomolar level.
本文报道了一种双杂配钌（II）配合物，即4,7-双（2-氨乙基氨基）-1,10-菲咯啉，用于对剧毒化学战剂光气进行选择性“开启”检测。探针表现出聚集诱导发光（AIE）特性，分子内运动受限是AIE活性的原因。在CHCl/CHCN [95:5（v/v）]溶剂混合物中，聚集后形成了独特的自组装囊泡结构，这得到了透射电子显微镜、场发射扫描电子显微镜和原子力显微镜研究的支持。与其他竞争性化学战剂相比，探针在CHCN中对光气表现出快速且高度选择性的发光开启响应，检测限低（13.9 nM）。中的2-氨乙基氨基基团作为亲核加成到光气羰基中心的反应位点，并发生分子内环化。光气介导反应的最终产物，已通过电喷雾电离质谱和氢核磁共振（NMR）光谱得到证实，其中含有2-咪唑啉酮基团。用光气对进行的氢核磁共振滴定支持了反应机理，也表明光气在两个2-氨乙基氨基位点同时发生反应。首次通过单晶X射线衍射证实了含有环化2-咪唑啉酮基团的光气反应产物的晶体结构，这无疑验证了反应机理。三线态时间相关密度泛函理论计算表明，的弱发光主要归因于非发光MC态的存在。与光气的环化反应以及相应的2-咪唑啉酮产物的形成使中的发光MLCT态增加，这是发光增强的关键原因。此外，还制备了一种低成本的便携式试纸条，用于纳摩尔水平光气气体的实时选择性监测。
