Photoresponsive Binding Dynamics in High?Affinity Cucurbit[8]uril?Dithienylethene Host?Guest Complexes

The use of external stimuli to control the binding kinetics in supramolecular systems is critical importance for development advanced molecular machines and devices. In this work, a study focused on water-soluble host-guest system based cucurbit[8]uril two dithienylethene (DTE) photoswitches reported. It shown that DTE guest comprising anionic sulfonate side arms appended pyridinium moieties, formation/dissociation pseudorotaxane structures slowed down by more than 100000-fold with respect its bipyridinium analogue. decrease ingression rate leads emergence competitive metastable product open isomer has an important influence overall kinetics. Moreover, dissociation demonstrated be approximately 100-fold slower closed (t1/2=107 h vs. t1/2=1.2 isomer) allowing over light.