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Photoswitchable Carbohydrate‐Based Macrocyclic Azobenzene: Synthesis, Chiroptical Switching, and Multistimuli‐Responsive Self‐Assembly
Author(s) -
Lin Chaoqi,
Maisonneuve Stéphane,
Métivier Rémi,
Xie Juan
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201703461
Subject(s) - azobenzene , circular dichroism , chirality (physics) , cyclohexane , moiety , chemistry , thermal stability , photochemistry , crystallography , stereochemistry , molecule , organic chemistry , chiral symmetry breaking , physics , quantum mechanics , nambu–jona lasinio model , quark
Abstract A one‐pot O ‐alkylation mediated macrocyclization approach has been used for the synthesis of carbohydrate‐based macrocyclic azobenzene. The synthesized macrocycle can be reversibly isomerized between E and Z isomers upon UV or visible irradiation with excellent photostability and thermal stability ( t 1/2 =51 days at 20 °C for the Z isomer). A chirality transfer from the chiral sugar unit to azobenzene was observed by circular dichroism (CD). DFT and TD‐DFT calculations were performed to calculate the optimal geometry and the theoretical absorption and CD spectra. Comparison of the experimental CD spectra with the theoretical ones suggests that both E ‐ and Z‐macrocycles adopt preferentially P ‐helicity for the azobenzene moiety. Furthermore, the macrocycle showed gelation ability in cyclohexane and ethanol with multistimuli‐responsive behavior upon exposure to environmental stimuli including thermal‐, photo‐, and mechanical responses. Moreover, these organogels display temperature‐dependent helical inversion, which can be tuned by a repeated heating–cooling procedure.