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Shi Y, Li C, Di J, Xue Y, Jia Y, Duan J, Hu X, Tian Y, Li Y, Sun C, Zhang N, Xiong Y, Jin T, Chen P. Polycationic Open-Shell Cyclophanes: Synthesis of Electron-Rich Chiral Macrocycles, and Redox-Dependent Electronic States. Angew Chem Int Ed Engl 2024:e202402800. [PMID: 38411404 DOI: 10.1002/anie.202402800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 02/20/2024] [Accepted: 02/23/2024] [Indexed: 02/28/2024]
Abstract
π-Conjugated chiral nanorings with intriguing electronic structures and chiroptical properties have attracted considerable interests in synthetic chemistry and materials science. We present the design principles to access new chiral macrocycles (1 and 2) that are essentially built on the key components of main-group electron-donating carbazolyl moieties or the π-expanded aza[7]helicenes. Both macrocycles show the unique molecular conformations with a (quasi) figure-of-eight topology as a result of the conjugation patterns of 2,2',7,7'-spirobifluorenyl in 1 and triarylamine-coupled aza[7]helicene-based building blocks in 2. This electronic nature of redox-active, carbazole-rich backbones enabled these macrocycles to be readily oxidized chemically and electrochemically, leading to the sequential production of a series of positively charged polycationic open-shell cyclophanes. Their redox-dependent electronic states of the resulting multispin polyradicals have been characterized by VT-ESR, UV-vis-NIR absorption and spectroelectrochemical measurements. The singlet (ΔES-T = -1.29 kcal mol-1) and a nearly degenerate singlet-triplet ground state (ΔES-T(calcd) = -0.15 kcal mol-1 and ΔES-T(exp) = 0.01 kcal mol-1) were proved for diradical dications 12+2• and 22+2•, respectively. Our work provides an experimental proof for the construction of electron-donating new chiral nanorings, and more importantly for highly charged polyradicals with potential applications in chirospintronics and organic conductors.
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Affiliation(s)
- Yafei Shi
- Beijing Institute of Technology, Chemistry, CHINA
| | - Chenglong Li
- Beijing Institute of Technology, Chemistry, CHINA
| | - Jiaqi Di
- Beijing Institute of Technology, Chemistry, CHINA
| | - Yuting Xue
- Beijing Institute of Technology, Chemistry, CHINA
| | - Yawei Jia
- Beijing Institute of Technology, Chemistry, CHINA
| | - Jiaxian Duan
- Beijing Institute of Technology, Chemistry, CHINA
| | - Xiaoyu Hu
- Beijing Institute of Technology, Chemistry, CHINA
| | - Yu Tian
- Beijing Institute of Technology, Chemistry, CHINA
| | - Yanqiu Li
- Beijing Institute of Technology, Chemistry, CHINA
| | - Cuiping Sun
- Beijing Institute of Technology, Chemistry, CHINA
| | - Niu Zhang
- Beijing Institute of Technology, Analysis and Testing Centre, CHINA
| | - Yan Xiong
- Beijing Institute of Technology, Analysis and Testing Centre, CHINA
| | - Tianyun Jin
- University of California San Diego Scripps Institution of Oceanography, Biotechnology and Biomedicine, UNITED STATES
| | - Pangkuan Chen
- Beijing Institute of Technology, Chemistry and Chemical Engineering, South 5 Zhongguancun Street, 102488, Beijing, CHINA
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