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Mechanistic Insights into the Triplet Sensitized Photochromism of Diarylethenes
Author(s) -
Fredrich Sebastian,
Morack Tobias,
Sliwa Michel,
Hecht Stefan
Publication year - 2020
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202000877
Subject(s) - diarylethene , photochromism , photochemistry , photoisomerization , microsecond , ultrafast laser spectroscopy , excited state , singlet state , femtosecond , chemistry , spectroscopy , triplet state , molecule , materials science , laser , optics , organic chemistry , physics , isomerization , quantum mechanics , nuclear physics , catalysis
Operating photoswitchable molecules repetitively and reliably is crucial for most of their applications, in particular in (opto)electronic devices, and related to reversibility and fatigue resistance, which both critically depend on the photoisomerization mechanism defined by the substitution pattern. Two diarylethene photoswitches bearing biacetyl triplet sensitizers either at the periphery or at the core were investigated using both stationary as well as transient UV/Vis absorption spectroscopy ranging from the femtosecond to the microsecond time scale. The diarylethene with two biacetyl moieties at the periphery is switching predominantly from the triplet excited state, giving rise to an enhanced fatigue resistance. In contrast, the diarylethene bearing one diketone at the photoreactive inner carbon atom cyclizes from the singlet excited state and shows significantly higher quantum yields for both cyclization and cycloreversion.