Supra‐dendron Gelator Based on Azobenzene–Cyclodextrin Host–Guest Interactions: Photoswitched Optical and Chiroptical Reversibility |
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| Authors: | Fan Xie Guanghui Ouyang Dr Long Qin Prof?Dr Minghua Liu |
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| Affiliation: | 1. CAS Key Laboratory of Colloid, Interface and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing, P. R. China;2. Collaborative Innovation Centre of Chemical Science and Engineering, Tianjin, P. R. China |
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| Abstract: | A novel amphiphilic dendron ( AZOC8GAc ) with three l ‐glutamic acid units and an azobenzene moiety covalently linked by an alkyl spacer has been designed. The compound formed hydrogels with water at very low concentration and self‐assembled into chiral‐twist structures. The gel showed a reversible macroscopic volume phase transition in response to pH variations and photo‐irradiation. During the photo‐triggered changes, although the gel showed complete reversibility in its optical absorptions, only an incomplete chiroptical property change was achieved. On the other hand, the dendron could form a 1:1 inclusion complex through a host–guest interaction with α‐cyclodextrin (α‐CD), designated as supra‐dendron gelator AZOC8GAc/α‐CD . The supra‐dendron showed similar gelation behavior to that of AZOC8GAc , but with enhanced photoisomerization‐transition efficiency and chiroptical switching capacity, which was completely reversible in terms of both optical and chiroptical performances. The self‐assembly of the supra‐dendron is a hierarchical or multi‐supramolecular self‐assembling process. This work has clearly illustrated that the hierarchical and multi‐supramolecular self‐assembling system endows the supramolecular nanostructures or materials with superior reversible optical and chiroptical switching. |
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| Keywords: | chiral twist chiroptical switching gels photoresponsiveness supramolecular chemistry |
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