Programmable photoresponsive materials based on a single molecule via distinct topochemical reactions. Issue 47 (26th November 2021)

• Record Type: Journal Article
• Authors: Wei, Xiao; Li, Bao; Yang, Zhiqiang; Zhong, Ronglin; Wang, Yufei; Chen, Yanan; Ding, Zeyang; Men, Guangwen; Yang, Zairan; Zhang, Houyu; Yang, Bing; Xu, Weiqing; Jiang, Shimei
• Is Part Of: Chemical science. Volume 12:Issue 47(2021)
• Page Start: 15588
• Page End: 15595
• Publication Date: 2021-11-26
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d1sc04053g
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : Two crystals with different hierarchical architectures are observed based on a single molecule, achieving different types of [2 + 2] photocycloaddition. Finally, controllable photoactuators and light-writable materials are successfully fabricated. Abstract : Engineering the preorganization of photoactive units remains a big challenge in solid-state photochemistry research. It is of not only theoretical importance in the construction of topochemical reactions but also technological significance in the fabrication of advanced materials. Here, a cyanostilbene derivative, ( Z )-2-(3, 5-bis(trifluoromethyl)phenyl)-3-(naphthalen-2-yl) acrylonitrile (BNA ), was crystallized into two polymorphs under different conditions. The two crystals, BNA-α and BNA-β, have totally different intra-π-dimer and inter-π-dimer hierarchical architectures on the basis of a very simple monomer, which provides them with distinct reactivities, functions and photoresponsive properties. Firstly, two different types of solid-state [2 + 2] photocycloaddition reaction: (i) a typical olefin–olefin cycloaddition reaction within the symmetric π-dimers of BNA-α and (ii) an unusual olefin-aromatic ring cycloaddition reaction within the offset π-dimers of BNA-β have been observed, respectively. Secondly, the crystal of BNA-α can be bent to 90° without any fracture, exhibiting outstanding flexibility upon UV irradiation, while the reversible photocycloaddition/thermal cleavage process (below 100 °C) accompanied by unique fluorescence changes can be achieved in the crystal of BNA-β . Finally, micro-scale photoactuators and light-writable anti-counterfeiting materials have been successfully fabricated. This work paves a simple way to construct smart materials through a bottom-up way that is realized by manipulating hierarchical architectures in the solid state.