Long‐Distance Rate Acceleration by Bulk Gold

We report on a very unusual case of surface catalysis involving azobenzenes in contact with a Au(111) surface. A rate acceleration of the cis–trans isomerization on gold up to a factor of 1300 compared to solution is observed. By using carefully designed molecular frameworks, the electronic coupling...

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Bibliographic Details
Published in:Angewandte Chemie 2019-05, Vol.131 (20), p.6646-6650
Main Authors: Schlimm, Alexander, Löw, Roland, Rusch, Talina, Röhricht, Fynn, Strunskus, Thomas, Tellkamp, Tobias, Sönnichsen, Frank, Manthe, Uwe, Magnussen, Olaf, Tuczek, Felix, Herges, Rainer
Format: Article
Language:English
Subjects:
Acceleration
Azobenzol
Catalysis
Chemistry
Coupling (molecular)
Density distribution
Gold
Isomerization
Katalyse
Kinetics
Oberflächenspektroskopie
Reaction kinetics
Schwingungsspektroskopie
Selbstorganisation
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Summary:We report on a very unusual case of surface catalysis involving azobenzenes in contact with a Au(111) surface. A rate acceleration of the cis–trans isomerization on gold up to a factor of 1300 compared to solution is observed. By using carefully designed molecular frameworks, the electronic coupling to the surface can be systematically tuned. The isomerization kinetics of molecules with very weak coupling to the metal is similar to that found in solution. For their counterparts with strong coupling, the relaxation rate is shown to depend on the spin‐density distribution in the triplet states of the molecules. This suggests that an intersystem crossing is involved in the relaxation process. Aside from their impact on catalytic processes, these effects could be used to trigger reactions over long distances. Ferngesteuert: Azobenzole, die aufrecht auf einer Goldoberfläche stehen, isomerisieren um mehrere Größenordnungen schneller von cis nach trans als in Lösung. Eine Kupplungseinheit erlaubt es, zwischen diesen beiden Extremen zu justieren. Untersuchungen zeigen, dass der Beschleunigung ein Spinwechsel zugrunde liegt, der in Lösung verboten ist, aber hier über elf Bindungen und eine Distanz von 14 Å durch die Goldoberfläche vermittelt wird.
ISSN:0044-8249
1521-3757
DOI:10.1002/ange.201814342