Elastic Photomechanical\nOrganic Single Crystals with\nDual Photoswitch Units for an Extended Absorption Band

Molecular crystals that can generate mechanical motion\nin response\nto external light are promising candidates for photoactuators, which\nare expected to have applications in microrobotics, artificial muscles,\nsmart switches, microfluidic systems, oscillators, etc. However, most\nof the molecular crystals are brittle, which leads to poor processability\nand easy failure during use. Furthermore, most of the crystals are\nactuated by UV light, which may be harmful to human health. Here,\nwe successfully synthesized an elastically flexible crystal that can\nundergo Z/E isomerization to achieve backlight bending under visible\nlight irradiation. The origin of elastic flexibility was explored\nby analyzing the packing structure and intermolecular interactions.\nThe photochemical reaction routine was confirmed by analysis of single-crystal\nstructure, <sup>1</sup>H NMR and FTIR spectra. The results presented\nin this work may provide a way to design flexible crystals that can\nbe actuated by visible light and facilitate the application of photoswitch\nmolecules.