Reliable Determination of Photoreaction Kinetics and Cyclization/Cycloreversion Quantum Yields for Dithienylethene Switches

A universal and flexible model fully describing photoreaction kinetics in dithienylethene (DTE) systems is presented. The proposed method enables reliable determination of photocyclization and photocycloreversion quantum yields at various conditions. Most importantly, it is applicable to a broad range of photoswitch concentrations and accounts for competitive reactions, such as annulation of the closed form. By employing both analytical and numerical solutions to the kinetic equations, we achieve consistent results: the numerical method ensures high accuracy in quantum yield determination, while the analytical method allows for the prediction of DTE photoreaction behavior. The robustness of the model was validated across four distinct DTE photoswitches under varying concentrations, solvents, excitation wavelengths conditions, demonstrating its broad applicability and reliability.