Breaking the semi-quinoid structure: Spin-switching from strongly coupled singlet to polarized triplet state

Prince Ravat, Yoshio Teki, Yoshikazu Ito, Elena Gorelik, Martin Baumgarten

    Research output: Contribution to journalArticlepeer-review

    12 Citations (Scopus)

    Abstract

    2,7-TMPNO (4,5,9,10-tetramethoxypyrene-2,7-bis(tert-butylnitroxide)) was found to exist in semi-quinoid form with unprecedented strong intramolecular magnetic exchange interaction of 2J/kB=1185 K operating over a distance of 10 Å. Structural transformations with the activation energy of ΔEeq=949 K were observed by varying the temperature, from more quinoid structure at low temperature to more biradicaloid structure at higher temperature. Moreover, this molecule undergoes a transient spin transition from singlet to polarized triplet state upon photoexcitation revealed by TREPR spectroscopy. The spin Hamiltonian parameters were determined to be S=1, g=2.0065, D=-0.0112 cm-1, and E=-0.0014 cm-1 by spectral simulation with the hybrid Eigenfield/exact diagonalization method.

    Original languageEnglish
    Pages (from-to)12041-12045
    Number of pages5
    JournalChemistry - A European Journal
    Volume20
    Issue number38
    DOIs
    Publication statusPublished - 2014 Sep 15

    Keywords

    • EPR spectroscopy
    • density functional calculations
    • magnetic exchange interactions
    • pyrenes
    • semi-quinoid

    ASJC Scopus subject areas

    • Catalysis
    • Organic Chemistry

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