Synthesis of Anthracene‐Based Cyclic π‐Clusters and Elucidation of their Properties Originating from Congested Aromatic Planes
Synthesis of Anthracene‐Based Cyclic π‐Clusters and Elucidation of their Properties Originating from Congested Aromatic Planes
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基于蒽的环状 π 团簇的合成及其源自稠密芳香平面的性质的阐明
DOI：
10.1002/anie.202013349
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Takashi Kubo
中科院分区：
文献类型：
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作者：
Tomohiko Nishiuchi;Kazuki Kisaka;Takashi Kubo
讨论了具有两个和四个蒽单元的基于蒽的环状 π 簇的合成和性质。最佳环化条件是根据镍（0）介导的反应确定的，该反应提供环状蒽二聚体作为主要产物。由于 HOMO-LUMO 间隙变窄，使两个蒽平面以面对面的方式靠近会导致吸收红移。由于高 π 拥塞，环状蒽二聚体表现出多刺激响应性。例如，对蒽二聚体进行光照射可得到其光异构体，该异构体具有长于1.65 Å的CC键，在温和加热下可以发生热回复。这使得光异构体（无色）能够机械致变色为原始的蒽二聚体（红色）。在晶态下也观察到光致异构化，伴随着晶体跳跃或塌陷，即光致突效应。
Synthesis and properties of anthracene‐based cyclic π‐clusters which possess two and four anthracene units are discussed. The optimal cyclization conditions were determined based on a nickel(0)‐mediated reaction that afforded a cyclic anthracene dimer as the major product. Bringing two anthracene planes in close proximity in a face‐to‐face manner resulted in red‐shifted absorption owing to the narrowing of the HOMO–LUMO gap. The cyclic anthracene dimer exhibits multi‐stimuli responsiveness due to high π‐congestion. For example, photoirradiation on the anthracene dimer affords its photoisomer having C−C bonds that are longer than 1.65 Å, which can undergo thermal reversion under gentle heating. This enabled mechanochromism of the photoisomer (colorless) to the original anthracene dimer (red). Photoisomerization was also observed in the crystalline state, accompanied by crystal jumping or collapsing, that is, the photosalient effect.