TY - JOUR
A1 - Kuntze, Kim
A1 - Viljakka, Jani
A1 - Titov, Evgenii
A1 - Ahmed, Zafar
A1 - Kalenius, Elina
A1 - Saalfrank, Peter
A1 - Priimagi, Arri
T1 - Towards low-energy-light-driven bistable photoswitches
BT - ortho-fluoroaminoazobenzenes
JF - Photochemical & photobiological sciences / European Society for Photobiology
N2 - Thermally stable photoswitches that are driven with low-energy light are rare, yet crucial for extending the applicability of photoresponsive molecules and materials towards, e.g., living systems. Combined ortho-fluorination and -amination couples high visible light absorptivity of o-aminoazobenzenes with the extraordinary bistability of o-fluoroazobenzenes. Herein, we report a library of easily accessible o-aminofluoroazobenzenes and establish structure-property relationships regarding spectral qualities, visible light isomerization efficiency and thermal stability of the cis-isomer with respect to the degree of o-substitution and choice of amino substituent. We rationalize the experimental results with quantum chemical calculations, revealing the nature of low-lying excited states and providing insight into thermal isomerization. The synthesized azobenzenes absorb at up to 600 nm and their thermal cis-lifetimes range from milliseconds to months. The most unique example can be driven from trans to cis with any wavelength from UV up to 595 nm, while still exhibiting a thermal cis-lifetime of 81 days.
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Y1 - 2022
U6 - https://doi.org/10.1007/s43630-021-00145-4
SN - 1474-905X
SN - 1474-9092
VL - 21
IS - 2
SP - 159
EP - 173
PB - Springer
CY - Heidelberg
ER -