An unprecedented polyoxometalate-based hybrid solid constructed from a neutral metal-organic macrocycle and Dawson polyoxotungstate anions

The self-assembly procedure of a Dawson-type polyoxotungstate with pyridine-2,6-dicarboxylate (H₂pdc) and copper^II ions produces an exquisite supramolecular aggregation. In the structure, a neutral cucurbit[n]uril-like metal-organic macrocycle is formed of six copper centers and six pdc^2- ligands, while a pair of Dawson-type polyoxotungstates are linked to the bottom and top portals of this macrocycle at the joint with the alkali metal ions. A control experiment was carried out to produce a different metalloligand-supported hybrid (instead of the metallomacrocycle) to verify the structure-directing role of Dawson polyanions in the title compound. In addition, the photoluminescent and magnetic properties of the hybrid solid have also been investigated.