Supramolecular organic framework based on cyclopentanocucurbit[6]uril and benzimidazole compounds

In this paper, a crystalline supramolecular organic framework was constructed based on cyclopentanocucurbit[6]uril (CyP 6 Q[6]) and five benzimidazole compounds [2-aminobenzimidazole (G1), 2-methylbenzimidazole (G2), 2-hydroxymethylbenzimidazole (G3), 2-phenylbenzimidazole (G4), 2-(2-pyridyl) -benzimidazole (G5)] through host-guest interaction, with the Single crystal X-ray diffraction analysis showing that CyP 6 Q[6] and Gn(n=1-5) formed 1:1 host-guest inclusion complexes by hydrogen bonding, respectively. The type of substituent (R group) in the guest determines the mode of interaction with CyP6Q[6], where the benzimidazole rings of G1-G4 are encapsulated in the cavity of CyP6Q[6] with the R group located outside its ports, whereas the R group (pyridinyl group) of G5 enters the cavity of CyP6Q[6] with the benzimidazole ring exposed outside its ports. Interestingly, under the ion-dipole interaction, the inclusion complexes form an '8′ shaped supramolecular organic framework by stacking, and due to the different characteristics of the R group and the binding mode, supramolecular channels with different sizes are formed.