A1 Journal article (refereed)
Towards low-energy-light-driven bistable photoswitches : ortho-fluoroaminoazobenzenes (2022)

Kuntze, K., Viljakka, J., Titov, E., Ahmed, Z., Kalenius, E., Saalfrank, P., & Priimagi, A. (2022). Towards low-energy-light-driven bistable photoswitches : ortho-fluoroaminoazobenzenes. Photochemical and Photobiological Sciences, 21(2), 159-173. https://doi.org/10.1007/s43630-021-00145-4

JYU authors or editors

Publication details

All authors or editors: Kuntze, Kim; Viljakka, Jani; Titov, Evgenii; Ahmed, Zafar; Kalenius, Elina; Saalfrank, Peter; Priimagi, Arri

Journal or series: Photochemical and Photobiological Sciences

ISSN: 1474-905X

eISSN: 1474-9092

Publication year: 2022

Publication date: 10/12/2021

Volume: 21

Issue number: 2

Pages range: 159-173

Publisher: Springer

Publication country: Germany

Publication language: English

DOI: https://doi.org/10.1007/s43630-021-00145-4

Publication open access: Openly available

Publication channel open access: Partially open access channel

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/78993


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.

Keywords: photochemistry; aromatic compounds; fluorine

Free keywords: photochemistry

Contributing organizations

Ministry reporting: Yes

Reporting Year: 2022

Preliminary JUFO rating: 1

Last updated on 2022-20-09 at 14:25