Reactivity of an aromatic σ,σ,σ-triradical:: The 2,4,6-tridehydropyridinium cation
Reactivity of an aromatic σ,σ,σ-triradical:: The 2,4,6-tridehydropyridinium cation
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DOI：
10.1002/anie.200701732
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发表时间：
2007-01-01
影响因子：
16.6
通讯作者：
Kenttaemaa, Hilkka I.
中科院分区：
文献类型：
--
作者：
Jankiewicz, Bartlomiej J.;Adeuya, Anthony;Kenttaemaa, Hilkka I.
某些σ型、以碳为中心的单自由基和双自由基，即脱氢芳烃和二脱氢芳烃，在有机合成、新有机材料的开发以及有机化合物的生物活性中发挥着重要作用。[1, 2]因此，大量的研究集中在它们的性质上。[1-5]相比之下，相关的σ、σ、σ-三自由基（三脱氢芳烃）仍然难以捉摸。由于实验研究这种高活性物质的困难，几乎所有对三脱氢芳烃进行的研究本质上都是计算性的。 [6]据我们所知，关于三脱氢芳烃的唯一实验研究是 Wenthold 等人对 1, 3, 5-三脱氢苯进行的热化学测量。 [7] Sander 等人对 1, 2, 3-三氢化苯的红外检测[8]三脱氢芳烃的化学性质似乎完全未被探索。我们在此报告了对带正电荷的三脱氢芳烃（2,4,6-三脱氢吡啶鎓阳离子）的动力学反应性研究 (5)。该三自由基的气相反应与两种相关的、先前未报道的 σ, σ双自由基、2, 4-二脱氢吡啶鎓阳离子 (3) 和 2, 6-二脱氢吡啶鎓阳离子 (4)，以及两种 σ-单自由基、4-脱氢吡啶鎓阳离子 (1) 和 2-脱氢吡啶鎓阳离子 (2) 的气相反应进行了比较。
Certain σ-type, carbon-centered mono-and biradicals, the dehydro-and didehydroarenes, play an important role in organic synthesis, development of new organic materials, and the biological activity of organic compounds.[1, 2] Therefore, numerous investigations have focused on their properties.[1–5] In contrast, the related σ, σ, σ-triradicals (tridehydroarenes) remain elusive. Almost all studies carried out on tridehydroarenes are computational in nature owing to the difficulty in studying such highly reactive species experimentally.[6] To the best of our knowledge, the only experimental studies reported for tridehydroarenes are thermochemical measurements on 1, 3, 5-tridehydrobenzene by Wenthold et al.[7] and IR detection of 1, 2, 3-tridehydrobenzene by Sander et al.[8] The chemical properties of tridehydroarenes appear to be entirely unexplored.We report here a kinetic reactivity study on a positively charged tridehydroarene, the 2, 4, 6-tridehydropyridinium cation (5). The gas-phase reactions of this triradical are compared to those of two related, previously unreported σ, σbiradicals, 2, 4-didehydropyridinium cation (3) and 2, 6-didehydropyridinium cation (4), as well as two σ-monoradicals, 4-dehydropyridinium cation (1) and 2-dehydropyridinium cation (2).