Photoexcited triplet states of UV-B absorbers: Ethylhexyl triazone and diethylhexylbutamido triazone

Takumi Tsuchiya, Azusa Kikuchi, Nozomi Oguchi-Fujiyama, Kazuyuki Miyazawa, Mikio Yagi

    • 1 Citations

    Abstract

    The excited states of UV-B absorbers, ethylhexyl triazone (EHT) and diethylhexylbutamido triazone (DBT), have been studied through measurements of UV absorption, fluorescence, phosphorescence, triplet-triplet absorption and electron paramagnetic resonance spectra in ethanol. The energy levels of the lowest excited singlet (S1) and triplet (T1) states and quantum yields of fluorescence and phosphorescence of EHT and DBT were determined. In ethanol at 77 K, the deactivation process of EHT and DBT is predominantly fluorescence, however, a significant portion of the S1 molecules undergoes intersystem crossing to the T1 state. The observed phosphorescence spectra, T1 lifetimes and zero-field splitting parameters suggest that the T1 state of EHT can be assigned to a locally excited 3ππ∗ state within p-(N-methylamino)benzoic acid, while the T1 state of DBT can be assigned to a locally excited 3ππ∗ state within p-(N-methylamino)benzoic acid or p-amino-N-methylbenzamide. The quantum yields of singlet oxygen generation by EHT and DBT were determined by time-resolved near-IR phosphorescence measurements in ethanol at room temperature. EHT and DBT did not exhibit significantly antioxidative properties by quenching singlet oxygen, in contrast to the study by Lhiaubet-Vallet et al.

    Original languageEnglish
    Pages (from-to)807-814
    Number of pages8
    JournalPhotochemical and Photobiological Sciences
    Volume14
    Issue number4
    DOIs
    StatePublished - 2015 Apr 1

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    Ethanol
    Fluorescence
    Singlet Oxygen
    Benzoic Acid
    Luminescent Measurements
    Electron Spin Resonance Spectroscopy
    Temperature

    ASJC Scopus subject areas

    • Physical and Theoretical Chemistry

    Cite this

    Photoexcited triplet states of UV-B absorbers : Ethylhexyl triazone and diethylhexylbutamido triazone. / Tsuchiya, Takumi; Kikuchi, Azusa; Oguchi-Fujiyama, Nozomi; Miyazawa, Kazuyuki; Yagi, Mikio.

    In: Photochemical and Photobiological Sciences, Vol. 14, No. 4, 01.04.2015, p. 807-814.

    Research output: Contribution to journalArticle

    Tsuchiya, Takumi; Kikuchi, Azusa; Oguchi-Fujiyama, Nozomi; Miyazawa, Kazuyuki; Yagi, Mikio / Photoexcited triplet states of UV-B absorbers : Ethylhexyl triazone and diethylhexylbutamido triazone.

    In: Photochemical and Photobiological Sciences, Vol. 14, No. 4, 01.04.2015, p. 807-814.

    Research output: Contribution to journalArticle

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