Closed Pentaaza[9]helicene and Hexathia[9]/[5]helicene: Oxidative Fusion Reactions of ortho-Phenylene-Bridged Cyclic Hexapyrroles and Hexathiophenes

Fengkun Chen, Takayuki Tanaka, Yong Seok Hong, Tadashi Mori, Dongho Kim, Atsuhiro Osuka

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22 Citations (Scopus)

Abstract

Oxidative fusion reactions of ortho-phenylene-bridged cyclic hexapyrroles and hexathiophenes furnished novel closed helicenes in a selective manner. X-Ray diffraction analysis unambiguously revealed the structures to be a closed pentaaza[9]helicene, the longest azahelicene reported so far, and an unexpected double-helical structure of hexathia[9]/[5]helicene, whose formation was assumed to result from multiple oxidative fusion along with a 1,2-aryl shift. The pentaaza[9]helicene exhibited well-defined emission with high fluorescence quantum yield (ΦF=0.31) among the known [9]helicenes. Chiral resolution of the racemic pentaaza[9]helicene and hexathia[9]/[5]helicene were achieved by chiral-phase HPLC and the enantiomers were characterized by circular dichroism spectra and DFT calculations.

Original languageEnglish
Pages (from-to)14688-14693
Number of pages6
JournalAngewandte Chemie - International Edition
Volume56
Issue number46
DOIs
Publication statusPublished - 2017 Nov 13

Bibliographical note

Funding Information:
The work at Kyoto was supported by JSPS KAKENHI (grant numbers JP25220802, JP16K13952, JP26810021, and JP16H00909). The work at Yonsei was supported by the Global Research Laboratory (GRL) Program funded by the Ministry of Science, ICT & Future, Korea (2013K1A1A2A02050183). T.M. thanks the JSPS KAKENHI (Grant Numbers JP15H03779, JP15K13642, JP16KK0111, JP17H05261), Asahi Glass Foundation, and Cosmetology Research Foundation for financial support. The authors thank Prof. Dr. Hiromitsu Maeda and Dr. Yohei Haketa (Ritsu-meikan University) for MALDI-TOF MS measurement.

Publisher Copyright:
© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)

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