Supramolecular self-assemblies of perhydroxycucurbit[5]uril with Keggin-type heteropolyacids

We report the preparation and single crystal X-ray diffraction analysis of three supramolecular self-assemblies based on perhydroxycucurbit[5]uril {(HO)10Q[5]}, Keggin-type heteropolyacids (HPAs), and potassium or barium cations. Crystallographic data revealed that all 3D self-assemblies are constructed by a stack of 2D layered structures composed of (HO)10Q[5]/K+ or (HO)10Q[5]/Ba2+ complexes cations and HPAs anions. Although there are differences in 2D layered structures, all the driving force comes from the outer surface interactions of (HO)10Q[5] including: (1) typical hydrogen bonding by hydroxyl groups and atypical hydrogen bonding by methylene on the outer surface of (HO)10Q[5]; (2) dipole interaction between the positively charged methylene or carbonyl carbon atoms of (HO)10Q[5] and the negatively charged oxygen atoms of the HPAs; (3) The electrostatic interaction between the (HO)10Q[5]/metal cations and the HPAs anions plays a main role in self-assembling.