Department of Chemistry, University of Toronto, 80 St. George St., Toronto, Ontario, M5S3H6, Canada.
Angew Chem Int Ed Engl. 2018 Mar 19;57(13):3322-3326. doi: 10.1002/anie.201713118. Epub 2018 Feb 21.
A room-temperature-stable crystalline cyclic (alkyl)(amino)nitrenium cation 2 features cationic nitrogen atom with a smaller HOMO-LUMO gap compared to that of a 1,2,3-triazolium 5 (an N-heterocyclic nitrenium cation). The low-lying LUMO of 2 results in an enhanced electrophilicity, which allowed for the formation of Lewis adducts with neutral Lewis bases, such as Me P, nBu P, and IiPr. The N-based Lewis acid 2 also forms an FLP with tBu P but subsequently reacts with (PrS) to cleave the S-S bond. Both experimental and theoretical results suggest that the Lewis acidity of 2 is stronger than its N analogues.
一种室温稳定的晶态环状（烷基）（氨基）氮鎓阳离子 2 具有比 1,2,3-三唑鎓 5（一种 N-杂环氮鎓阳离子）更小的阳离子氮原子 HOMO-LUMO 能隙。2 的低占据 LUMO 导致其亲电性增强，从而能够与中性路易斯碱（如 MeP、nBuP 和 IiPr）形成路易斯加合物。基于 N 的路易斯酸 2 也与 tBuP 形成 FLP，但随后与（PrS）反应以切断 S-S 键。实验和理论结果均表明，2 的路易斯酸度强于其 N 类似物。
