Donor–donor’–acceptor triads based on [3.3]paracyclophane with a 1,4-dithiafulvene donor and a cyanomethylene acceptor: Synthesis, structure, and electrochemical and photophysical properties

Katsuya Sako, Tomoya Hasegawa, Hiroyuki Onda, Michito Shiotsuka, Motonori Watanabe, Teruo Shinmyozu, Sachiko Tojo, Mamoru Fujitsuka, Tetsuro Majima, Yasukazu Hirao, Takashi Kubo, Tetsuo Iwanaga, Shinji Toyota, Hiroyuki Takemura

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    2 Citations (Scopus)

    Abstract

    Donor–donor’–acceptor triads (1, 2), based on [3.3]paracyclophane ([3.3]PCP) as a bridge, with electron-donating properties (D’) using 1,4-dithiafulvene (DTF; TTF half unit) as a donor and dicyanomethylene (DCM; TCNE half unit) or an ethoxycarbonyl-cyanomethylene (ECM) as an acceptor were designed and synthesized. The pulse radiolysis study of 1a in 1,2-dichloroethane allowed the clear assignment of the absorption bands of the DTF radical cation (1a·+), whereas the absorption bands due to the DCM radical anion could not be observed by γ-ray radiolysis in 2- methyltetrahydrofuran rigid glass at 77 K. Electrochemical oxidation of 1a first generates the DTF radical cation (1a·+), the absorption bands of which are in agreement with those observed by a pulse radiolysis study, followed by dication (1a2+). The ESR spectrum of 1a·+ showed a symmetrical signal with fine structure and an ESR simulation predicted that the spin of 1a·+ is delocalized over S and C atoms of the DTF moiety and the central C atom of the trimethylene bridge bearing the DTF moiety. Pulse radiolysis, ESR, and electrochemical studies indicate that the DTF radical cation of 1a·+ is more stable than that of 6·+, and the latter shows a strong tendency to dimerize. This result indicates that the [3.3]PCP moiety as a bridge can stabilize the DTF radical cation more than the 1,3-diphenylpropane moiety because of kinetic stability due to its rigid structure and the weak electronic interaction of DTF and DCM moieties through [3.3]PCP.

    Original languageEnglish
    Pages (from-to)11407-11416
    Number of pages10
    JournalChemistry - A European Journal
    Volume24
    Issue number44
    DOIs
    Publication statusPublished - Jan 1 2018

    All Science Journal Classification (ASJC) codes

    • Catalysis
    • Organic Chemistry

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