Warren Gabrielle I, Barker Joshua E, Zakharov Lev N, Haley Michael M
Department of Chemistry & Biochemistry, University of Oregon, Eugene, Oregon 97403, United States.
CAMCOR, University of Oregon, Eugene, Oregon 97403, United States.
Org Lett. 2021 Jul 2;23(13):5012-5017. doi: 10.1021/acs.orglett.1c01514. Epub 2021 Jun 15.
Addressing the instability of antiaromatic compounds often involves protection with bulky groups and/or fusion of aromatic rings, thus decreasing paratropicity. We report four naphthothiophene-fused -indacene isomers, one of which is more antiaromatic than parent -indacene. This surprising result is examined computationally through nucleus-independent chemical shift XY calculations and experimentally via nuclear magnetic resonance spectroscopy, X-ray crystallography, ultraviolet-visible spectrophotometry, and cyclic voltammetry, with the latter two indicating that this molecule possesses the lowest highest occupied molecular orbital-lowest unoccupied molecular orbital energy gap observed for heterocycle-fused -indacene.
解决反芳香族化合物的不稳定性通常涉及用庞大基团进行保护和/或稠合芳香环，从而降低同芳香性。我们报道了四种萘并噻吩稠合茚并四烯异构体，其中一种比母体茚并四烯更具反芳香性。通过独立核化学位移XY计算对这一惊人结果进行了计算研究，并通过核磁共振光谱、X射线晶体学、紫外可见分光光度法和循环伏安法进行了实验研究，后两者表明该分子具有杂环稠合茚并四烯中观察到的最低最高占据分子轨道-最低未占据分子轨道能隙。
