Department of Chemistry, Faculty of Science, Shizuoka University, Oya, Shizuoka 422-8529, Japan.
J Phys Chem A. 2013 Jun 6;117(22):4688-97. doi: 10.1021/jp4016678. Epub 2013 May 28.
Recently synthesized septulene is a unique cycloarene molecule in that no macrocyclic conjugation circuits can be chosen from the π-system. This molecule has essentially no superaromatic stabilization energy (SSE) and can be viewed as an ideal nonsuperaromatic macrocycle. SSEs for kekulene and other cycloarenes are also very small. In these hydrocarbons, a macrocycle formed by fused benzene rings effectively suppresses not only the aromaticity inherent in macrocyclic (4n+2)-site conjugation circuits but also the antiaromaticity inherent in macrocyclic (4n±1)-site circuits. Comparative study of superaromaticity in multilayered coronoid hydrocarbons revealed that not only SSE but also the HOMO contribution to SSE is minimized in odd-layered coronoids.
最近合成的 septulene 是一种独特的环芳烃分子，因为其π 体系中没有可以选择的大环共轭电路。这个分子几乎没有超芳香稳定能（SSE），可以看作是一个理想的非超芳香大环。kekulene 和其他环芳烃的 SSE 也很小。在这些碳氢化合物中，由稠合苯环形成的大环不仅有效地抑制了大环（4n+2）-位共轭电路固有的芳香性，也抑制了大环（4n±1）-位电路固有的反芳香性。对多层冠状碳氢化合物中超芳香性的比较研究表明，不仅 SSE，而且 HOMO 对 SSE 的贡献在奇数层冠状化合物中也最小化。
