The Solid-State Tautomerism of Donor-Acceptor Stenhouse Adduct Solvatomorphs

Donor-Acceptor Stenhouse Adducts (DASAs) are a class of photoresponsive molecules that isomerise reversibly with visible light. The isomerism manifests as an observable colour change through the breaking and reformation of the pi-conjugated core - photochromism. DASAs have been subject to synthetic and solution-state investigations since their discovery in 2014. This work seeks to understand the first-ever observed instance of solid-state switching of DASA single-crystals and the effect of solvation upon the switching properties. It is believed that the solvation of the crystal structure allows sufficient molecular freedom to undergo dramatic structural changes within the solid-state. The materials' response to temperature, humidity and mechanical force has also been investigated as a means of inducing solid-state switching of the material. This project's consequences could see DASAs being used in new real-world

applications as sensors, dopants in smart composite materials, and in the production of mechanically active materials for use in soft robotics and molecular motors.