TY - JOUR
T1 - Computational Design and Synthesis of a Deeply Red-Shifted and Bistable Azobenzene
AU - Konrad, David B.
AU - Savasci, Gökcen
AU - Allmendinger, Lars
AU - Trauner, Dirk
AU - Ochsenfeld, Christian
AU - Ali, Ahmed M.
N1 - Funding Information:
This work was supported by the SFB749 to D.T. and C.O. as well as a Georg Forster Research Fellowship (Alexander von Humboldt Foundation) to A.M.A. C.O. also acknowledges financial support by the Innovative Training Network “Computational Spectroscopy in Natural Sciences and Engineering” (ITN-COSINE). D.B.K. received funding from the European Union’s Framework Program for Research and Innovation Horizon 2020 (2014-2020) under the Marie Skłodowska-Curie Grant agreement no. 754388 (LMUResearchFellows) and from LMU Munich’s Institutional Strategy LMUexcellent within the framework of the German Excellence Initiative (no. ZUK22). A.M.A. is grateful to Prof. Dr. Klaus Wanner for hosting the second year of his AvH fellowship. We thank Prof. Ivan Huc for hosting revision experiments in his laboratory, Dr. Oliver Thorn-Seshold and Li Gao for their help with establishing a LED setup, Dr. Peter Mayer for X-ray analyses, as well as Marvin Thielert for helpful discussions.
PY - 2020/4/8
Y1 - 2020/4/8
N2 - We computationally dissected the electronic and geometrical influences of ortho-chlorinated azobenzenes on their photophysical properties. X-ray analysis provided the insight that trans-tetra-ortho-chloro azobenzene is conformationally flexible and thus subject to molecular motions. This allows the photoswitch to adopt a range of red-shifted geometries, which account for the extended n → π∗ band tails. On the basis of our results, we designed the di-ortho-fluoro di-ortho-chloro (dfdc) azobenzene and provided computational evidence for the superiority of this substitution pattern to tetra-ortho-chloro azobenzene. Thereafter, we synthesized dfdc azobenzene by ortho-chlorination via 2-fold C-H activation and experimentally confirmed its structural and photophysical properties through UV-vis, NMR, and X-ray analyses. The advantages include near-bistable isomers and an increased separation of the n → π∗ bands between the trans- and cis-conformations, which allows for the generation of unusually high levels of the cis-isomer by irradiation with green/yellow light as well as red light within the biooptical window.
AB - We computationally dissected the electronic and geometrical influences of ortho-chlorinated azobenzenes on their photophysical properties. X-ray analysis provided the insight that trans-tetra-ortho-chloro azobenzene is conformationally flexible and thus subject to molecular motions. This allows the photoswitch to adopt a range of red-shifted geometries, which account for the extended n → π∗ band tails. On the basis of our results, we designed the di-ortho-fluoro di-ortho-chloro (dfdc) azobenzene and provided computational evidence for the superiority of this substitution pattern to tetra-ortho-chloro azobenzene. Thereafter, we synthesized dfdc azobenzene by ortho-chlorination via 2-fold C-H activation and experimentally confirmed its structural and photophysical properties through UV-vis, NMR, and X-ray analyses. The advantages include near-bistable isomers and an increased separation of the n → π∗ bands between the trans- and cis-conformations, which allows for the generation of unusually high levels of the cis-isomer by irradiation with green/yellow light as well as red light within the biooptical window.
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U2 - 10.1021/jacs.9b10430
DO - 10.1021/jacs.9b10430
M3 - Article
C2 - 32207943
AN - SCOPUS:85082700838
VL - 142
SP - 6538
EP - 6547
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 14
ER -