Modulation of Fluorescence/Photomechanical Response Based on Dual Photoresponsive Molecules via Cocrystals

Abstract

Modulation of the properties of molecular crystals by means of cocrystals is a common means, and it is not common for two solid-state photoreactions to occur simultaneously in the same system. Herein, we designed a dual-photoresponsive molecular crystal system to obtain two crystals with different properties by combining different stoichiometric ratios of 9-anthracenecarboxylic acid (9AC) and 4-styrenepyridine (SPE) molecules. In addition to the different fluorescence properties, neither 9AC nor SPE undergoes photodimerization in Cry1, whereas both undergo it in Cry2 under UV irradiation. The change in molecular stacking simultaneously realized the switching on/off of the photodimerization reactions for the two molecules. The information encryption design was also realized using the fluorescence change of the solidstate photoreactions. The study provides a new reference for solid-state photoreactions and the design of photomechanical crystalline materials.