A multi-stage single photochrome system for controlled photoswitching responses

The ability of molecular photoswitches to convert on/off responses into large macroscale property change is fundamental to light-responsive materials. However, moving beyond simple binary responses necessitates the introduction of new elements that control the chemistry of the photoswitching process at the molecular scale. To achieve this goal, we designed, synthesized and developed a single photochrome, based on a modified donor-acceptor Stenhouse adduct (DASA), capable of independently addressing multiple molecular states. The multi-stage photoswitch enables complex switching phenomena. To demonstrate this, we show spatial control of the transformation of a three-stage photoswitch by tuning the population of intermediates along the multi-step reaction pathway of the DASAs without interfering with either the first or final stage. This allows for a photonic three-stage logic gate where the secondary wavelength solely negates the input of the primary wavelength. These results provide a new strategy to move beyond traditional on/off binary photochromic systems and enable the design of future molecular logic systems. Moving beyond binary responses in photoswitches necessitates the introduction of new elements along their switching pathway. Now, a modified donor-acceptor Stenhouse adduct (DASA) capable of independently addressing multiple molecular states has been developed. This enables the transformation of a three-stage photoswitch to be controlled by regulating intermediates along the DASA reaction pathway.

Automated summary

This study reports a novel photoswitch that can independently control multiple molecular states, enabling the transformation of a three-stage photoswitch to be controlled by regulating intermediates along the reaction pathway.