Synthesis and Structural Elucidation of Bisdibenzocorannulene in Multiple Redox States. (6th August 2021)

• Record Type: Journal Article
• Authors: Li, Bo; Yang, Chenxin; Wang, Xinhao; Li, Guangwu; Peng, Wangwang; Xiao, Huiping; Luo, Shenglian; Xie, Sheng; Wu, Jishan; Zeng, Zebing
• Is Part Of: Angewandte Chemie. Volume 133:Number 36(2021)
• Page Start: 19943
• Page End: 19949
• Publication Date: 2021-08-06
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202104520
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: We report an anti ‐folded bowl‐shaped bisdibenzocorannulene (BDBC ) featuring a new chair‐cyclohexane‐like hexagon as a bridge of two dibenzocorannulene moieties. The neutral compound showed multiple redox‐active properties and could be converted to the corresponding redox states through chemical reduction or oxidation. Chemical reduction of BDBC by stoichiometric addition of metallic potassium in the presence of [18]crown‐6 ether, provided a radical anion BDBC .− and a dianion BDBC 2−, respectively; while chemical oxidation by silver hexafluoroantimonate(V), converted the neutral compound to an open‐shell singlet diradical dication (BDBC .. ) 2+ . The structural consequences of both electron‐reduction and oxidation were closely related to the release of ring‐strain of the bowl‐shaped π‐scaffold and imposed steric hindrance of the hexagonal bridge. In addition, the unusual open‐shell nature of the dication could mainly be attributed to the changing of localized antiaromaticity in the closed‐shell structure to delocalized character in the biradical, and thus the emergence of weakly bonded π‐electrons. Abstract : Chemical reduction/oxidation of a new type of curved π‐network (BDBC ) provided access to its multiple redox states. For the one‐electron reduced state, the BDBC .− was characterized by single‐crystal X‐ray diffraction as a solvent‐separated radical anion; while the two‐electron oxidized state was revealed as an unusual singlet diradical dication (BDBC .. ) 2+ . As a consequence of their redox behaviours, their structures and ring currents have large differences.