Premium
Bending, Curling, Rolling, and Salient Behavior of Molecular Crystals Driven by [2+2] Cycloaddition of a Styrylbenzoxazole Derivative
Author(s) -
Wang Haoran,
Chen Peng,
Wu Zhu,
Zhao Jinyu,
Sun Jingbo,
Lu Ran
Publication year - 2017
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201705325
Subject(s) - cycloaddition , curling , photochemistry , chemistry , excited state , bending , crystallography , materials science , composite material , organic chemistry , physics , atomic physics , catalysis
We report interesting photomechanical behaviors of the dynamic molecular crystals of ( E )‐2‐(2,4‐dichlorostyryl)benzo[d]oxazole ( BOACl24 ). The photosalient effect of the rod‐like crystal based on a metal‐free olefin driven by photodimerization is observed. Moreover, the needle‐like crystals of BOACl24 exhibit a reversible bending away from a UV light source. The nanofibers curl easily under UV irradiation in an organogel, in which the photo‐induced rolling of a small slice occurs. This suggests that the rapid release of the accumulated strain during photodimerization may lead to a photosalient effect, and the bending or curling happens when the strain is released slowly. Notably, [2+2] cycloaddition takes place between two different conformational isomers of BOACl24 on account of the rotation of the benzoxazole ring around the C−C bond in an excited state before photodimerization. Such topo‐photochemical reaction has not been reported elsewhere.