Controlled Molecular Self-Assembly Behaviors between Cucurbituril and Bispyridinium Derivatives

Two stable supramolecular loops (1 and 2) were successfully constructed by the molecular recognition of cucurbit[8]uril (CB[8]) and the homoditopic bispyridiniurn derivatives (3 and 4). Interestingly, the interconversion of molecular loops and [2]pseudorotaxanes could be reversibly switched under neutral and acidic condition, exhibiting the controlled electrochemical and spectroscopic behaviors.