Antiaromatic 1,5‐Diaza‐s‐indacenes
Antiaromatic 1,5‐Diaza‐s‐indacenes
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抗芳香族化合物 1,5-二氮杂-二茚苯
DOI：
10.1002/anie.202109003
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发表时间：
2021
期刊：
影响因子：
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通讯作者：
Shinokubo Hiroshi
中科院分区：
文献类型：
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作者：
Hanida Kensuke;Kim Jinseok;Fukui Norihito;Tsutsui Yusuke;Seki Shu;Kim Dongho;Shinokubo Hiroshi
s-茚并苯是一种经典的非交替烃，在环状π共轭体系中含有12个π电子。在此，我们报告其氮掺杂类似物，1，5-二氮杂-s-引达省。1，5-二氮杂-s-引达省是由市售的2，5-二氯苯-1，4-二胺通过两步转化容易地制备的，该两步转化由钯催化的Larock环化与二芳基乙炔随后夺氢组成。由此获得的1，5-二氮杂-s-引达省表现出明显的反芳香性，如在明确的键长交替，HOMO-LUMO禁戒跃迁，和环电流。与母体引达省相比，由于亚胺型氮原子的存在，1，5-二氮杂-s-引达省显示出更高的电子接受能力。1，5-二氮杂-s-引达省核与外围芳基有效共轭，这使得能够微调吸收光谱和氧化还原性质。1，5-二氮杂-s-引达省的两种可能的局部形式在其能量方面进行了比较。
s‐Indacene is a classical non‐alternant hydrocarbon that contains 12 π‐electrons in a cyclic π‐conjugation system. Herein, we report its nitrogen‐doped analogue, 1,5‐diaza‐s‐indacene. 1,5‐Diaza‐s‐indacenes were readily prepared from commercially available 2,5‐dichlorobenzene‐1,4‐diamine through a two‐step transformation consisting of a palladium‐catalyzed Larock cyclization with diaryl acetylenes followed by hydrogen abstraction. The thus obtained 1,5‐diaza‐s‐indacenes exhibited distinct antiaromaticity, as manifested in clear bond‐length alternation, a forbidden HOMO–LUMO transition, and a paratropic ring current. As compared to the parents‐indacene, the 1,5‐diaza‐s‐indacenes showed higher electron‐accepting ability owing to the presence of imine‐type nitrogen atoms. The 1,5‐diaza‐s‐indacene core is effectively conjugated with the peripheral aryl groups, which enables fine‐tuning of the absorption spectra and redox properties. The two possible localized forms of 1,5‐diaza‐s‐indacene were compared in terms of their energetic aspects.