Syntheses, structures, and properties of a series of supramolecular hybrids based on Keggin or Wells–Dawson polyoxometalates and 4,4′-bipyridines

Abstract

Three new organic–inorganic supramolecular hybrids, namely, [4,4′-Hbpy] 2[HPW 12O 40]·H 2O (4,4′-bpy = 4,4′-bipyridine, 1), [4,4′-H 2bpy] 6[P 2W 18O 62] 2·6H 2O ( 2), [4,4′-H 2bpy] 5[HP 2W 18O 62] 2 ( 3), were hydrothermally synthesized in situ at different pH. Single crystal X-ray diffraction analyses show that complex 1 constructed from Keggin polyoxoanions and 4,4′-bipyridine organic ligands, exhibits an extended three-dimensional supramolecular network via hydrogen bonding, while 3D supramolecular network of complexes 2–3 were based on Wells–Dawson polyoxoanions and 4,4′-bipyridine organic ligands. The structural differences of complexes 1–3 indicated that the self-assembly process is pH-dependent. Complexes 1–3 have good photocatalytic activity for the photodegradation of methyl orange in the presence of H 2O 2 under UV light irradiation.