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Updated: Jun 10, 2026

Self-assembling Morphologies Obtained from Helical Polycarbodiimide Copolymers and Their Triazole Derivatives
Published on: February 7, 2017
Light-switchable Janus [2]rotaxanes based on α-cyclodextrin derivatives bearing two recognition sites linked with
Shujing Li1, Daisuke Taura, Akihito Hashidzume
1Department of Macromolecular Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan.
Abstract:
Two Janus [2]rotaxanes, 5a and 5b, with α-cyclodextrin (α-CD) derivatives substituted on the 6-position with two recognition sites (azobenzene and heptamethylene (C7)) that were linked with linkers of different lengths (oligo(ethylene glycol) with a degree of polymerization equal to 2 or approximately 21) were synthesized and characterized. 2D ROESY NMR spectroscopy and circular dichroism (cd) spectra demonstrated that the recognition site of the α-CD moiety was switched by photoisomerization of the azobenzene moiety in 5a and 5b. The different size changes of 5a and 5b in hydrodynamic radius (R(H)) owing to the different length of linker between two recognition sites were observed by pulse-field-gradient spin-echo NMR spectroscopy. The kinetic results indicated that the different length of linker had no or a weak effect for the photoisomerization process of 5a and 5b.
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