Rationally designed small molecular photoswitches based on the ESIPT mechanism of salicylaldehyde hydrazone derivatives

Abstract Organic photoswitches show significant and reversible changes of color and optical properties under the action of light, which has attracted extensive attentions due to their application prospects in the fields of optical information storage, decorative and protective packaging materials, optical device materials, photocatalysis and bioscience. Herein, a series of small organic photoswitches based on salicylaldehyde hydrazone derivatives were synthesized. They have very simple molecular structures but exhibited good photochromic properties of UV–Vis absorption and fluorescence spectra under the irradiation with 365 nm ultraviolet light. And the substituents and solvents have important effects on the photochromic properties of the resulting photoswitches. This work may provide an alternative scheme for development of photochromic materials.