Azepine‐ or Azocine‐Embedded Hexabenzocoronene Derivatives as Nitrogen‐Doped Saddle or Saddle‐Helix Nanographenes. (12th October 2021)

• Record Type: Journal Article
• Authors: An, Peng; Li, Ranran; Ma, Bin; He, Run‐Ying; Zhang, Yi‐Kang; Xiao, Ming‐Jun; Zhang, Bin
• Is Part Of: Angewandte Chemie. Volume 133:Number 46(2021)
• Page Start: 24683
• Page End: 24688
• Publication Date: 2021-10-12
• Subjects: nanographenes -- nitrogen-doped structure -- polyaromatic compounds -- saddle-helix -- saddle-shaped structures; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202110538
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: Two novel nitrogen‐doped, hexa‐peri‐hexabenzocoronene (HBC)‐based nanographenes (NGs) 1 and 2 bearing an azepine and an azocine at the fjord region, respectively, were synthesized and characterized. Notably, structure 1 was synthesized by Diels–Alder reaction of cyclic alkene and tetrachlorothiophene‐S, S‐dioxide, followed by Suzuki–Miyaura cross‐coupling and Scholl‐type reactions, which represents a modified strategy to construct NGs. The azo‐heptagon‐embedded NG 1 leads to a saddle shape, and the azo‐octagon‐embedded NG 2 exhibits a distorted saddle‐helix conformation with the largest torsion angle recorded so far in [5]helicenes. As a result, the different structural topographies for NGs 1 and 2 lead to significant changes in the optical properties including UV absorption and fluorescent emission. Additionally, the 8π‐heterocycles azepine and azocine in the NGs 1 and 2 exhibited obvious antiaromatic properties. Abstract : Two nitrogen‐doped nanographenes bearing an azepine ring and an azocine ring, respectively, were synthesized and saddle‐shaped and saddle‐helix structures were obtained. Notably, two synthetic routes were adopted for the synthesis, the azepine‐embedded polyaromatic was prepared by using cyclic alkene and tetrachlorothiophene‐S, S‐dioxide instead of typical alkyne and tetraphenylcyclopenta‐2, 4‐dien‐1‐one.