WUT researchers' paper in Angewandte Chemie International Edition

Dithienylethenes (DTEs) are a fascinating class of compounds with optical properties. They undergo fast and reversible isomerisation between their open and closed forms when exposed to ultraviolet or visible radiation. By rationally modifying their molecular structure, the optical properties of these systems can be precisely controlled. This approach was used to create numerous complex functional materials with specific properties, which are subsequently modulated by switching DTE units. As a result, these photoswitches have found successful applications in optoelectronics, logic circuits, medicine, biology, chemo- and biosensors, as well as in catalysis.

Although there is evidence that DTE compounds can be readily incorporated into complex materials, numerous limitations still need to be addressed to broaden their practical use and enable a transition from model laboratory experiments to real-life applications. Achieving this requires a deep understanding of mechanisms underlying the photoswitching process, supported by precise determination of descriptive parameters such as the quantum yield of the photoreaction, the cyclisation conversion, and reaction half-life.

The presented publication refers to the development of a new model describing photoswitching reactions in dithienylethene systems. The proposed method facilitates reliable determination of quantum yields for both photocyclisation and photoreversion under a variety of conditions. Most importantly, the method can be applied over a broad concentration range and accounts for competing reactions. 

“As part of the project, we examined photoswitches based on dithienylethene (DTE) structure, with particular interest in systems containing transition-metal centres such as iron, zinc, cobalt, copper, or nickel. The research posed a significant challenge as right at the beginning we encountered limitations in modelling those systems arising from the imperfections of existing methods,” emphasises Krzysztof Durka, PhD, from the Faculty of Chemistry at WUT. “To overcome those limitations, we proposed an innovative approach to the mechanism of photoswitching between isomers, enabling precise prediction of compound behaviour under various conditions and supporting their further design for the applications mentioned above. The research was published in the prestigious journal Angewandte Chemie International Edition and was highlighted on the inside front cover of the journal.”

Consistent results were obtained using both analytical solutions and numerical kinetic equations. The numerical method ensures high precision in determining the quantum yield, while the analytical approach enables prediction of the course of the DTE photoreaction. The universality of the model was confirmed for four different DTE photoswitches across a wide range of concentrations, solvents, and excitation times.

The paper was prepared as part of the implementation of the NCN OPUS (2019/33/B/ST4/03144) grant, with the University of Warsaw as the leader of the consortium (Radosław Kamiński, PhD), and the Warsaw University of Technology as a partner (represented by Krzysztof Durka, PhD).

Link to the paper: https://doi.org/10.1002/anie.202514591

Link to the cover: https://doi.org/10.1002/anie.2025-m0512050000