Electrochromic and unique chiroptical properties of helically deformed tetraarylquinodimethanes generated from less-hindered dicationic precursors upon reduction

Takanori Suzuki, Yuto Sakano, Tomohiro Iwai, Shinichi Iwashita, Youhei Miura, Ryo Katoono, Hidetoshi Kawai, Kenshu Fujiwara, Yasushi Tsuji, Takanori Fukushima

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2 Citations (Scopus)


Electron-donating 1,1,4,4-tetraarylbutadiene is a representative electrochromic dye, and the same chromophore can be found in 9,10-bis(diarylmethylene)-9,10-dihydrophenanthrene (dibenzo-oQD) albeit in a fixed s-cis geometry. Unlike thermodynamically unstable 7,7,8,8-tetraaryl-o- quinodimethane, spontaneous electrocyclization is prohibited by dibenzo-annulation. Several derivatives of dibenzo-oQD were successfully generated despite highly strained geometry caused by steric hindrance between the bulky diarylmethylene units. Their precursors are phenanthrene-9,10-diyl bis(diarylmethylium) dyes (PDM2+) stabilized by four electron-donating alkoxy groups. The redox pairs of dibenzo-oQD/PDM2+ exhibit vivid change in color upon redox interconversion (electrochromism). Both dibenzo-oQD and PDM2+adopt a helical conformation, whose configuration is unstable. When a chiral alkoxy substituent is attached on each of the aryl groups, the point chirality is successfully transmitted to helicity of PDM2+. Resulting diastereomeric biasing is the key for dibenzo-oQD/PDM2+to exhibit the two-way-output response (e.g., UV-vis and CD). In addition, much more strained quinodimethane derivatives, 1,2-bis(diarylmethylene)acenaphthene and 1,16-diaryldibenzo[b,n]perylene, were also generated from the dicationic precursors, demonstrating that the reductive transformation can serve as a useful protocol to generate severely deformed π-conjugated systems.

Original languageEnglish
Pages (from-to)507-516
Number of pages10
JournalPure and Applied Chemistry
Issue number4
Publication statusPublished - 2014 Apr 17
Externally publishedYes



  • Chirality
  • Dication
  • Dye
  • Electrochiroptics
  • Electrochromism
  • ISNA-15
  • Redox system
  • Strained molecules

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)

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