Dithieno[3,4-b:3',4'-d]arsole: A Novel Class of Hetero[5]radialenes
Dithieno[3,4-b:3',4'-d]arsole: A Novel Class of Hetero[5]radialenes
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Dithieno[3,4-b:3,4-d]arsole：一类新型杂[5]辐射烯
DOI：
10.1002/ejoc.202000442
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发表时间：
2020
影响因子：
2.8
通讯作者：
Naka Kensuke
中科院分区：
文献类型：
--
作者：
Urushizaki Aya;Yumura Takashi;Kitagawa Yuichi;Hasegawa Yasuchika;Imoto Hiroaki;Naka Kensuke
[5]Radialene是一种不稳定的环烃，具有交叉共轭系统。将杂原子引入到[5]radialene骨架中是一种有效的稳定策略。由于三价砷原子比磷原子稳定得多，因此我们合成了一类新的杂[5]放射烯化合物二噻吩并[3，4-B：3 '，4'-d]arsole（1）。通过与二噻吩并[3，2-B：2 '，3'-d]arsole（2）的比较，对arsa[5]radialene的特征性质进行了实验和计算研究。通过X射线晶体学的结构分析和芳香性的计算评估揭示了1的径向烯特征。有趣的是，1显示磷光，而2只观察到荧光。含时密度泛函理论（TD-DFT）计算表明，在激发1时，系统间的交叉很容易发生。此外，通过计算阐明了通过Diels-桤木反应的二聚和/或低聚（其转化[5]辐烯）被规避以提供1的稳定性。
[5]Radialene is known as an unstable cyclic hydrocarbon with a cross‐conjugated system. Incorporation of heteroatoms into [5]radialene skeleton is an effective strategy for stabilization. Herein we synthesized dithieno[3,4‐b:3',4'‐d]arsole (1) as a novel class of hetero[5]radialenes since trivalent arsenic atom is much more stable than phosphorus one, which was used for hetero[5]radialene but unstable in air. The characteristic nature of the arsa[5]radialene was experimentally and computationally studied by comparing with the isomer, dithieno[3,2‐b:2',3'‐d]arsole (2). Structural analysis by X‐ray crystallography and computational evaluation of aromaticity revealed the radialene character of1. Interestingly,1showed phosphorescence though only fluorescence was observed for2. Time‐dependent density functional theory (TD‐DFT) calculations implied that intersystem crossing could readily occur upon excitation for1. Furthermore, it was computationally elucidated that dimerization and/or oligomerization via Diels‐Alder reaction, which convert [5]radialene, were circumvented to offer stability for1.