Giant Single‐Crystal Shape Transformation with Wide Thermal Hysteresis Actuated by Synergistic Motions of Molecular Cations and Anions. Issue 30 (14th May 2020)

• Record Type: Journal Article
• Authors: Wang, Xiao‐Lei; Xue, Jin‐Peng; Sun, Xiao‐Peng; Zhao, Yan‐Xin; Wu, Shu‐Qi; Yao, Zi‐Shuo; Tao, Jun
• Is Part Of: Chemistry. Volume 26:Issue 30(2020)
• Page Start: 6778
• Page End: 6783
• Publication Date: 2020-05-14
• Subjects: bistable materials -- mechanical properties -- molecular wheels -- phase transitions -- thermal hysteresis; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.202000845
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: Manipulating the collective molecular movements to implement macroscopic mechanical response of bulk material is attractive and challenging. Here, an organic‐inorganic hybrid single crystal is synthesized, which exhibits a giant macroscopic shape transformation with a remarkable thermal hysteretic feature. The colossal anisotropic shape change, which manifests as an abrupt elongation of ca. 9 % along the crystallographic c ‐axis and a concomitant contraction of ca. 9 % in a perpendicular direction, is induced by a significant reorientation of imidazolium, accompanied with a substantial configurational variation in CuBr4 2− complex anions. The synergistic motions of both the molecular cations and anions engender a remarkable large thermal hysteresis (>30 K) in the shape transformation of the single crystal, implying that this material may play a role in alternating memory media. Furthermore, due to the stable crystal lattice, a single crystal that demonstrates naked‐eye detectable large shape transformation was used as a thermal actuator to spontaneously control an electric circuit by temperature variation. Abstract : Switch it up : A single crystal of Cu II complex demonstrates an abrupt and reversible giant shape transformation with remarkable wide thermal hysteresis, as a consequence of synergetic actions of reorientation of molecular cations and geometric variation of complex anions. The giant shape deformation of single crystal can be used as a thermal actuator to spontaneously control a circuit by temperature variation.