All-Visible-Light Diarylethene Photoswitches and Control over Dynamic Conjugate Addition Reactions

Abstract

All-visible-light-driven photoswitches are gaining significant attention for their environmental friendliness and biocompatibility. Here, a series of visible-light responsive photoswitches is presented by embedding α,β-unsaturated 1,3-dicarbonyl motifs into the ethene bridge of dithienylethene (DTE) scaffolds. Through electronic modulation and π-conjugation extension, the absorption is redshifted into the visible range, enabling reversible photochromic ring-closure and ring-opening under blue and red light, respectively. Density functional theory calculations reveal that electron-withdrawing groups and extended conjugation narrow the HOMO–LUMO gap, enhancing photoswitching efficiency. Furthermore, these photoswitches also function as dynamic Michael acceptors, allowing visible-light-controlled CS bond formation and cleavage with great reversibility. The work described offers a versatile platform for visible-light-regulated dynamic covalent chemistry and paves the way for the development of recyclable, biocompatible materials.