A two-dimensional single-layer supramolecular organic framework that is driven by viologen radical cation dimerization and further promoted by cucurbit[8]uril

A two-dimensional supramolecular organic framework has been constructed in water from a rigid water-soluble triangular building block which is driven by the dimerization of three appended viologen radical cation units. Cucurbit[8]uril (CB[8]) further stabilizes the single-layer network by encapsulating the stacking viologen radical cation dimers. The new supramolecular networks have been characterized with UV-vis absorption, electron paramagnetic resonance, dynamic light scattering, solution and solid phase small angle X-ray diffraction, and AFM experiments. The aggregation behaviour is in sharp contrast to that of a triangular control compound, which only forms a discrete dimer or a 2 : 3 encapsulation complex in the absence or presence of CB[8].