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Upper Critical Solution Temperature‐Type Responsive Cyclodextrins with Characteristic Inclusion Abilities
Author(s) -
Zhu Li,
Liu Kun,
Zheng Shudong,
Zhang Xiacong,
Yan Jiatao,
Li Wen,
Zhang Afang
Publication year - 2021
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.202101283
Subject(s) - upper critical solution temperature , lower critical solution temperature , supramolecular chemistry , aqueous solution , chemistry , cloud point , phase transition , solubility , coacervate , chemical engineering , materials science , copolymer , organic chemistry , molecule , polymer , thermodynamics , biochemistry , physics , engineering
Water‐soluble and thermoresponsive macrocycles with stable inclusion toward guests are highly valuable to construct stimuli‐responsive supramolecular materials for versatile applications. Here, we develop such macrocycles – ureido‐substituted cyclodextrins (CDs) which exhibit unprecedented upper critical solution temperature (UCST) behavior in aqueous media. These novel CD derivatives showed good solubility in water at elevated temperature, but collapsed from water to form large coacervates upon cooling to low temperature. Their cloud points are greatly dependent on concentration and can be mediated through oxidation and chelation with silver ions. Significantly, the amphiphilicity of these CD derivatives is supportive to host‐guest binding, which affords them inclusion abilities to guest dyes. The inclusion complexation remained nearly intact during thermally induced phase transitions, which is in contrast to the switchable inclusion behavior of lower critical solution temperature (LCST)‐type CDs. Moreover, ureido‐substituted CDs were exploited to co‐encapsulate a pair of guest dyes whose fluorescence resonance energy transfer process can be switched by the UCST phase transition. We therefore believe these novel thermoresponsive CDs may form a new strategy for developing smart macrocycles and allow for exploring smart supramolecular materials.