TY  - JOUR
A1  - Goulet-Hanssens, Alexis
A1  - Rietze, Clemens
A1  - Titov, Evgenii
A1  - Abdullahu, Leonora
A1  - Grubert, Lutz
A1  - Saalfrank, Peter
A1  - Hecht, Stefan
T1  - Hole Catalysis as a General Mechanism for Efficient and Wavelength-Independent Z -> E Azobenzene Isomerization
JF  - CHEM
N2  - 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.
Y1  - 2018
U6  - https://doi.org/10.1016/j.chempr.2018.06.002
SN  - 2451-9294
VL  - 4
IS  - 7
SP  - 1740
EP  - 1755
PB  - Cell Press
CY  - Cambridge
ER  -