A Calix[4]resorcinarene-Copper(II) Based Supramolecular Nanocapsule with Encapsulated Polyoxometalates for Enhanced Photocatalytic Activity

The research on improving the photocatalytic activity of polyoxometalates (POMs) has attracted considerable attention. In this work, a functionalized calix[4]­resorcinarene ligand with four terpyridine groups (TPYR4A) was rationally designed, and then a POM-calix[4]­resorcinarene based inorganic–organic complex [Cu4Cl4(TPYR4A)]2[PWVI10WV2O40]­[PWVI12O40]·6DMA·8H2O (DMA= N,N′-dimethylacetamide) (1) was achieved by a self-assembly process. Strikingly, POM clusters were successfully encapsulated in noncovalent dimeric calix[4]­resorcinarene-copper­(II) based nanocapsules with a size of 3 nm. Markedly, 1 features a visible light absorption response with an optical band gap of 2.3 eV. More importantly, 1 exhibits obviously enhanced photocatalytic activity for oxidation of benzaldehyde upon simulated solar light excitation. Particularly, the photocatalytic performance of 1 is better than that of pure H3PW12O40 or a mixture of TPYR4A and H3PW12O40. This work offers a feasible strategy for designing POM-based hybrid materials with enhanced photocatalytic activity.