Hartinger M, Herm M, Schüßlbauer C, Köttner L, Guldi DM, Dube H, Müller C (2025)
Publication Type: Journal article
Publication year: 2025
Article Number: e202510626
In recent years, significant progress has been made in the effort to shift the absorption of photoresponsive molecules into the long-wavelength region of the electromagnetic spectrum. A breakthrough in this field was the recent development of π-extended indigoid photoswitches, i.e., peri-anthracenethioindigo (PAT), exhibiting all-red to near-infrared absorption. The excited-state isomerization mechanisms of this very new addition to the realm of photoswitching are currently not understood at all, prohibiting a rational further development. In this study, we present a combined theoretical and experimental approach, including (TD-)DFT and ADC(2) calculations as well as steady-state and time-resolved femtosecond spectroscopy, to explore the isomerization pathways of this photoswitch. Our findings show that E-to-Z photoisomerization on singlet potential energy surfaces (PESs) is highly unfavorable and instead shows that photoswitching proceeds on the T₁ PES. These insights enhance our understanding of thioindigoid photochemistry and demonstrate that extension of the π-system and peri-connectivity in the heterocycle unlock extremely favorable photoswitching properties along with the desirable red-shift in absorption. Reliable photoswitching from the triplet is achieved because of its favorable energy, which evades undesirable interference from oxygen quenching. These results pave the way for advancing thioindigoid-based photoswitches to improved performance and functionality in a rational way.
APA:
Hartinger, M., Herm, M., Schüßlbauer, C., Köttner, L., Guldi, D.M., Dube, H., & Müller, C. (2025). From Triplet to Twist: The Photochemical E/Z‐Isomerization Pathway of the Near‐Infrared Photoswitch peri‐Anthracenethioindigo. Angewandte Chemie International Edition. https://doi.org/10.1002/anie.202510626
MLA:
Hartinger, Martina, et al. "From Triplet to Twist: The Photochemical E/Z‐Isomerization Pathway of the Near‐Infrared Photoswitch peri‐Anthracenethioindigo." Angewandte Chemie International Edition (2025).
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