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Dihydroazulene‐Azobenzene‐Dihydroazulene Triad Photoswitches
Author(s) -
Mengots Alvis,
Erbs HillersBendtsen Andreas,
Doria Sandra,
Ørsted Kjeldal Frederik,
Machholdt Høyer Nicolai,
Ugleholdt Petersen Anne,
Mikkelsen Kurt V.,
Di Donato Mariangela,
Cacciarini Martina,
Brøndsted Nielsen Mogens
Publication year - 2021
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.202101533
Subject(s) - azobenzene , photoisomerization , photoswitch , triad (sociology) , photochromism , photochemistry , chemistry , materials science , isomerization , molecule , organic chemistry , psychoanalysis , catalysis , psychology
Photoswitch triads comprising two dihydroazulene (DHA) units in conjugation with a central trans‐ azobenzene (AZB) unit were prepared in stepwise protocols starting from meta ‐ and para ‐disubstituted azobenzenes. The para ‐connected triad had significantly altered optical properties and lacked the photoactivity of the separate photochromes. In contrast, for the meta ‐connected triad, all three photochromes could be photoisomerized to generate an isomer with two vinylheptafulvene (VHF) units and a cis‐ azobenzene unit. Ultrafast spectroscopy of the photoisomerizations revealed a fast DHA‐to‐VHF photoisomerization and a slower trans ‐to‐ cis AZB photoisomerization. This meta triad underwent thermal VHF‐to‐DHA back‐conversion with a similar rate of all VHFs, independent of the identity of the neighboring units, and in parallel thermal cis ‐to‐ trans AZB conversion. The experimental observations were supported by computation (excitation spectra and orbital analysis of the transitions).