Title
Supramolecular chirality induced by chiral solvation in achiral cyclic Azo-containing polymers: topological effects on chiral aggregation
Author
Lu Yin, Meng Liu, Yin Zhao, Shuangshuang Zhang, Wei Zhang, Zhengbiao Zhang, Xiulin Zhu
Year
2018
Journal
Polymer Chemistry
Abstract
Herein, a series of azobenzene (Azo)-containing side-chain cyclic polymers were successfully synthesized by combining atom transfer radical polymerization (ATRP) and Cu(I)-catalyzed azide/alkyne cycloaddition (CuAAc) “click” reaction. The aggregates of linear and cyclic Azo polymers in a dichloroethane/limonene mixed solvent were characterized by circular dichroism (CD) and UV-visible spectroscopy, demonstrating that the topological structural constraint and molecular mass of cyclic polymers have clear effects on the supramolecular chirality driven by a chiral solvent. The difference between linear and cyclic Azo aggregates in supramolecular chirality became less distinct with increasing molecular mass of Azo polymers. The chiroptical switch of cyclic Azo polymers was firstly constructed by trans–cis photoisomerization and cis–transheating-assisted reorganization processes. These interesting findings suggest that the cyclic topology has a clear influence on the behavior of supramolecular chirality induced by chiral limonene.
Instrument
J-815
Keywords
Circular dichroism, Polymers, Chemical stability, Stereochemistry