Chemical transformations of push-pull fluorenones: Push-pull dibenzodicyanofulvenes as well as fluorenone- And dibenzodicyanofulvene-tetracyanobutadiene conjugates

Shin Ichiro Kato, Tomokazu Kijima, Yoshihito Shiota, Tsukasa Abe, Satoshi Kuwako, Hidenori Miyauchi, Naoki Yoshikawa, Koji Yamamoto, Kazunari Yoshizawa, Toshitada Yoshihara, Seiji Tobita, Yosuke Nakamura

Research output: Contribution to journalArticle

Abstract

Push-pull fluorenones (FOs) were synthesized by treating a benzopentalenequinone (BPO) derivative with alkynes that bear an electron-rich aniline moietyviaa regioselective [4 + 2] cycloaddition (CA) followed by a [4 + 1] retrocycloaddition (RCA). The resulting FOs were readily converted into dibenzodicyanofulvenes (DBDCFs) by treatment with malononitrile in the presence of TiCl4and pyridine. The FOs and DBDCFs exhibit intramolecular charge-transfer (ICT) that manifests in absorptions at 350-650 nm and amphoteric electrochemical behavior. Furthermore, FOs and DBDCFs that contain a C-C bond react with tetracyanoethylene in a formal [2 + 2] CA followed by a retro-electrocyclization to afford sterically congested tetracyanobutadiene (TCBD) conjugates. The substituent (H or Me) on the aromatic ring adjacent to the butadiene moiety thereby determines whether the butadiene adopts an s-cisor s-transconformation, and thus controls the physicochemical properties of the resulting TCBDs. The TCBD conjugates exhibit ICT absorptions (≤800 nm) together with up to four reversible reduction steps.

Original languageEnglish
Pages (from-to)4198-4209
Number of pages12
JournalOrganic and Biomolecular Chemistry
Volume18
Issue number22
DOIs
Publication statusPublished - Jun 14 2020

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Physical and Theoretical Chemistry
  • Organic Chemistry

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