Zou Ya, Han Yi, Wu Shaofei, Hou Xudong, Chow Chi Hao Eugene, Wu Jishan
Department of Chemistry, National University of Singapore, 3 Science Drive 3, 117543, Singapore, Singapore.
Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Binhai New City, Fuzhou, 350207, China.
Angew Chem Int Ed Engl. 2021 Aug 2;60(32):17654-17663. doi: 10.1002/anie.202105427. Epub 2021 Jun 24.
A planar dibenzo-peri-hexacene derivative (2) was synthesized via FeCl -mediated Scholl reaction from a cyclopenta-fused perylene (CP) based polyphenylene precursor (1). However, an unexpected octagon-containing, negatively curved molecule (3) was obtained in nearly quantitative yield when 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and methanesulfonic acid (MeSO H) were used. Similar results were observed when two smaller-sized precursors containing one (4) or two CP units (5) were tested. X-ray crystallographic analysis also revealed that there is no close π-π stacking between neighboring π-conjugated skeletons. DFT calculations suggest a radical cation mechanism in the presence of FeCl while an arenium ion pathway for the DDQ/MeSO H mediated Scholl reaction, which can well explain the selective formation of hexagons and octagons under different conditions. The obtained compounds showed tunable optical and electrochemical properties.
通过基于环戊并苝（CP）的聚苯撑前体（1），经由FeCl₃介导的肖尔反应合成了一种平面二苯并苝并六烯衍生物（2）。然而，当使用2,3-二氯-5,6-二氰基-1,4-苯醌（DDQ）和甲磺酸（MeSO₃H）时，以几乎定量的产率得到了一种意外的含八元环的负曲率分子（3）。当测试含有一个（4）或两个CP单元（5）的两个较小尺寸的前体时，观察到了类似的结果。X射线晶体学分析还表明，相邻的π共轭骨架之间不存在紧密的π-π堆积。密度泛函理论计算表明，在FeCl₃存在下存在自由基阳离子机理，而DDQ/MeSO₃H介导的肖尔反应存在芳鎓离子途径，这可以很好地解释在不同条件下六边形和八边形的选择性形成。所得到的化合物表现出可调谐的光学和电化学性质。
