一个完全结合的平面异环 [9] 环
Stephan K Pedersen1, Kristina Eriksen1, Hans Ågren2,3
1Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark.
Journal of the American Chemical Society
|August 14, 2020
概括
研究人员合成了第一个 [9] 环,一种新的宏环芳香化合物,扩大了已知的环结构的极限. 这一突破为材料科学和有机化学提供了新的可能性.
科学领域:
- 有机化学
- 材料科学
- 超分子化学
背景情况:
- 完全芳香的[n]环,宏环芳香,以前限制在最多八个芳香环 (n=8).
- 高级[n]环素的合成 (n>8) 仍然是有机化学的一个未经探索的领域.
研究的目的:
- 为了合成和表征新的,高阶[n]循环素超出先前已知的n=8的极限.
- 研究这些新的宏循环系统的结构,电子和芳香特性.
主要方法:
- 在宏循环构造中使用了3,6-二氧化碳和glyoxal之间的高产度二元化凝聚反应.
- 使用单晶X射线衍射来确定合成的三维结构.
- 进行核独立化学转移 (NICS) 和诱导电流密度 (ACID) 异形计算以评估芳香性和电子性质.
主要成果:
- 第一个 [9]circulene (diazatrioxa[9]circulene) 和一个 [10]circulene类似物 (tetrahydro-diazatetraoxa[10]circulene) 已成功合成.
- 射线分析证实 [9] 环烯是完全平的,带有延长的环,表明应变诱导的平面性.
- 中心非芳香环中的交替键长和偏热环电流表明有显著的 [9] 放射共振贡献和诱导偏热性.
结论:
- 第一个 [9] 环烯的成功合成代表了宏环芳化合物领域的重大进步.
- 结构和电子特性,包括平面性和放射性特性,为应力芳香系统的行为提供了新的见解.
- 在非芳香核中观察到的诱导偏热性为探索先进材料的新电子和光物理性质开辟了道路.
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