Hole Catalysis as a General Mechanism for Efficient and Wavelength-Independent Z -> E Azobenzene Isomerization
- Whereas the reversible reduction of azobenzenes has been known for decades, their oxidation is destructive and as a result has been notoriously overlooked. Here, we show that a chain reaction leading to quantitative Z -> E isomerization can be initiated before reaching the destructive anodic peak potential. This hole-catalyzed pathway is accessible to all azobenzenes, without exception, and offers tremendous advantages over the recently reported reductive, radical-anionic pathway because it allows for convenient chemical initiation without the need for electrochemical setups and in the presence of air. In addition, catalytic amounts of metal-free sensitizers, such as methylene blue, can be used as excited-state electron acceptors, enabling a shift of the excitation wavelength to the far red of the azobenzene absorption (up to 660 nm) and providing quantum yields exceeding unity (up to 200%). Our approach will boost the efficiency and sensitivity of optically dense liquid-crystalline and solid photo-switchable materials.
Author details: | Alexis Goulet-HanssensORCiD, Clemens RietzeORCiDGND, Evgenii TitovORCiDGND, Leonora Abdullahu, Lutz Grubert, Peter SaalfrankORCiDGND, Stefan HechtORCiD |
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DOI: | https://doi.org/10.1016/j.chempr.2018.06.002 |
ISSN: | 2451-9294 |
Title of parent work (English): | CHEM |
Publisher: | Cell Press |
Place of publishing: | Cambridge |
Publication type: | Article |
Language: | English |
Date of first publication: | 2018/06/28 |
Publication year: | 2018 |
Release date: | 2021/11/01 |
Volume: | 4 |
Issue: | 7 |
Number of pages: | 16 |
First page: | 1740 |
Last Page: | 1755 |
Funding institution: | Alexander von Humboldt-FoundationAlexander von Humboldt Foundation; Fonds de Recherche du Quebec - Nature et Technologies (FQRNT); Daimler and Benz Foundation [32-02/14]; German Research FoundationGerman Research Foundation (DFG) [SFB 658]; European Research CouncilEuropean Research Council (ERC) [ERC-2012-StG 308117] |
Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Chemie |
DDC classification: | 5 Naturwissenschaften und Mathematik / 54 Chemie / 540 Chemie und zugeordnete Wissenschaften |
Peer review: | Referiert |
Publishing method: | Open Access / Bronze Open-Access |