Stereoselective Chiral Molecular Carbon Imides Featuring 12‐Fold [5]helicenes Around Four Cores

• Published in: Angewandte Chemie International Edition Vol. 62; no. 1; pp. e202214769 - n/a
• Main Authors: Liu, Guogang, Liu, Yujian, Zhao, Chengxi, Li, Yan, Wang, Zhaohui, Tian, He
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 02-01-2023
• Edition: International ed. in English
• Subjects: Carbon; Chirality; Cores; Diimide; Enantiomers; Helicene; Imides; Liquid chromatography; Molecular Carbon; Solubility; Stability; Stereoisomerism; Stereoisomers; Stereoselectivity; Symmetry; Stereoisomers; Stereoselectivity; Helicene; Molecular Carbon; Chirality
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202214769

Despite the great progress in research on molecular carbons containing multiple helicenes around one core, realizing the stereoselectivity of carbons containing multiple helicenes around more cores is still a great challenge. Herein, molecular carbon C204 featuring 12‐fold [5]helicenes around four cores was successfully constructed by using nine perylene diimide (PDI) units, and exhibits good solubility and stability. Despite 256 possible stereoisomers caused by the 12‐fold [5]helicenes, we only obtained one pair of enantiomers with D3 symmetry. There are four possible pairs of enantiomers with D3 symmetry, namely 7A, 7B, 7C and 7D. Theoretical and experimental results verify that the obtained structure belongs to 7C, which has the lowest energy. The enantiomers can also be separated by chiral HPLC. These results suggest that choosing PDIs as building blocks can not only improve the solubility and stability but also realize the stereoselectivity and chirality of molecular carbons.
A molecular carbon imide featuring 12‐fold [5]helicenes around four cores has been constructed using perylene diimide units. The structure exhibits high stereoselectivity and chirality, good solubility, and stability. Although there are four possible pairs of enantiomers with D3 symmetry, the results verify that the obtained structure belongs to the one having the lowest energy. The enantiomers can also be separated by HPLC on a chiral stationary phase.