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

Research output: Contribution to journalArticle

15 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

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All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)

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