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Zeitschriftenartikel:

B. Dereka, D. Svechkarev, A. Rosspeintner, A. Aster, M. Lunzer, R. Liska, A. Mohs, E. Vauthey:
"Solvent tuning of photochemistry upon excited-state symmetry breaking";
Nature Communications, 11 (2020), S. 1 - 11.



Kurzfassung englisch:
The nature of the electronic excited state of many symmetric multibranched donor-acceptor molecules varies from delocalized/multipolar to localized/dipolar depending on the environment. Solvent-driven localization breaks the symmetry and traps the exciton in one branch. Using a combination of ultrafast spectroscopies, we investigate how such excited-state symmetry breaking affects the photochemical reactivity of quadrupolar and octupolar A-(π-D)2,3 molecules with photoisomerizable A-π-D branches. Excited-state symmetry breaking is identified by monitoring several spectroscopic signatures of the multipolar delocalized exciton, including the S2 ← S1 electronic transition, whose energy reflects interbranch coupling. It occurs in all but nonpolar solvents. In polar media, it is rapidly followed by an alkyne-allene isomerization of the excited branch. In nonpolar solvents, slow and reversible isomerization corresponding to chemically-driven symmetry breaking, is observed. These findings reveal that the photoreactivity of large conjugated molecules can be tuned by controlling the localization of the excitation.

Schlagworte:
Inorganic, Nanoscale and Physical Chemistry, combination of ultrafast spectroscopies, photochemical reactivity of quadrupolar and octupolar A-(π-D)2,3 molecules with photoisomerizable A-π-D branches


"Offizielle" elektronische Version der Publikation (entsprechend ihrem Digital Object Identifier - DOI)
http://dx.doi.org/10.1038/s41467-020-15681-3


Erstellt aus der Publikationsdatenbank der Technischen Universitšt Wien.