Supramolecular interactions of bisbenzimidazolyl derivatives with cucurbit[7]uril, potential axle molecules bearing a novel fluorescent signal response

The supramolecular properties of cucurbit[7]uril and 1,ω-bisbenzimidazolyl derivatives have been studied by 1H NMR, fluorescence emission spectroscopy, and X-ray single crystal analysis. The distinctly fluorescent response behaviors indicated that the benzimidazole moiety here not only acts as the optical signaling unit for the pseudorotaxane system, but also behaves as a proton acceptor during the host–guest complexation. Furthermore, the fluorescent signals intensity could be adjusted by varying the alkylene spacer between the two benzimidazole moieties.