Title
Supra-dendron gelator based on Azobenzene-cyclodextrin Host-Guest interaction: Photoswitched Optical and Chiroptical reversibility
Author
Fan Xie, Long Qin, Minghua Liu
Year
2016
Journal
Chemistry A European Journal
Abstract
A novel amphiphilic dendron (AZOC8GAc) with three L-glutamic acid units and an azobenzene moiety covalently linked by an alkyl spacer was designed. The compound formed hydrogels with water in very low concentration and self-assembled into chiral twist structures. The gel showed a reversible macroscopic volume phase transition responding to pH variations and photo-irradiation. During the photo-triggered changes, although the gel showed a complete reversibility in their optical absorptions, only an incomplete chiroptical property was reached. On the other hand, the dendron could form a 1:1 inclusion complex via a host-guest interaction with -cyclodextrin (α-CD), designated as a supra-dendron gelator AZOC8GAc /α-CD. The supra-dendron showed a similar gelation behavior to that of AZOC8GAc but with an enhanced photoisomerization transition efficiency and chiroptical switching capacity, which was completely reversible both in the optical and chiroptical performances. The self-assembly of the supra-dendron is a hierarchical or multi supramolecular self-assembling process. The work clear illustrates that the hierarchical and multi-supramolecular self-assembling systems endows the supramolecular nanostructures or materials with superior reversible optical and chiroptical switching.
Instrument
J-810
Keywords
Circular dichroism, Stereochemistry, Chemical stability, Materials