Center for Self-assembly and Complexity, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea.
Department of Chemistry, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea.
Angew Chem Int Ed Engl. 2018 Jan 2;57(1):262-265. doi: 10.1002/anie.201710530. Epub 2017 Dec 4.
N-heterocyclic carbene (NHC) nitric oxide (NHCNO) radicals, which can be regarded as iminoxyl radicals stabilized by NHCs, were found to react with a series of silyl and alkyl triflates to generate the corresponding oxime ether radical cations. The structures of the resulting oxime ether radical cations were determined by X-ray crystallography, along with EPR and computational analysis. In contrast, lutidinium triflate produced a 1:1 mixture of [NHCNO ][OTf ] and [NHCNHOH ][OTf ] upon the reaction with NHCNO. This study adds an important example of stable singlet carbenes for stabilizing main-group radicals because of their π-conjugating effect, the synthesis and structures of which have not been reported previously.
氮杂环卡宾（NHC）一氧化氮（NHCNO）自由基可被视为氮杂环卡宾稳定的亚硝酰自由基，研究发现其可与一系列硅基和烷基三氟甲磺酸酯反应，生成相应的肟醚自由基阳离子。通过 X 射线晶体学、电子顺磁共振（EPR）和计算分析确定了生成的肟醚自由基阳离子的结构。相比之下，当与 NHCNO 反应时，六氢吡啶三氟甲磺酸酯生成了 [NHCNO][OTf]和 [NHCNHOH][OTf]的 1:1 混合物。由于其π共轭效应，本研究为稳定的单重态碳烯提供了一个稳定主族自由基的重要实例，而其合成和结构此前尚未报道。
