1. A Fused [5]Helicene Dimer with a Figure‐Eight Topology: Synthesis, Chiral Resolution, and Electronic Properties.
- Author
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Zhou, Qifeng, Hou, Xudong, Wang, Jinyi, Ni, Yong, Fan, Wei, Li, Zhengtao, Wei, Xiao, Li, Ke, Yuan, Wei, Xu, Zhuofan, Zhu, Manzhou, Zhao, Yanli, Sun, Zhe, and Wu, Jishan
- Subjects
RESOLUTION (Chemistry) ,ELECTRON delocalization ,RING formation (Chemistry) ,TOPOLOGY ,VINYL ethers ,ENANTIOMERS - Abstract
Chiral shape‐persistent molecular nanocarbons are promising chiroptical materials; their synthesis, however, remains a big challenge. Herein, we report the facile synthesis and chiral resolution of a double‐stranded figure‐eight carbon nanobelt 1 in which two [5]helicene units are fused together. Two synthetic routes were developed, and, in particular, a strategy involving Suzuki coupling‐mediated macrocyclization followed by Bi(OTf)3‐catalyzed cyclization of vinyl ether turned out to be the most efficient. The structure of 1 was confirmed by X‐ray crystallographic analysis. The isolated (P,P)‐ and (M,M)‐ enantiomers show persistent chiroptical properties with relatively large dissymmetric factors (|gabs|=5.4×10−3 and |glum|=1.0×10−2), which can be explained by the effective electron delocalization along the fully conjugated belt and the unique D2 symmetry. 1 exhibits local aromatic character with a dominant structure containing eight Clar's aromatic sextet rings. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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