Thermoresponsive cyclodextrins with switchable inclusion abilities

Abstract

Cyclodextrins (CDs) modified with oligoethylene glycols (OEGs) show unprecedented thermoresponsive properties in aqueous solutions and their phase transition temperatures can be mediated in the range of 24–63 °C depending on the ring size of CDs and the structure of the OEG units. Their synthesis, thermoresponsive behavior, and host-guest chemistry are described herein. Similar to the native CDs, these CD derivatives display strong inclusion ability for dyes below the phase transition temperatures. Moreover, the encapsulated dyes can be easily released due to the dehydration of OEG units at elevated temperatures, associated with an obvious color change of the aqueous solutions, which makes these CD species unique as scaffolds for colorimetric sensors.