Hydrothermal syntheses and structures of two novel polyoxometalate-based 3-D supramolecular architectures

Two supramolecular architectures based on polyoxometalates: [4,4′-Hbpy]2[Ni(4,4′-bpy)2(H2O)4][AsWVI11WVO40]·4H2O (1) and [4,4′-H2bpy]2[PMoVI9MoV3O40]·2H3O (2) (4,4′-bpy = 4,4′-bipyridine) have been prepared under hydrothermal conditions and characterized by elemental analyses, IR spectra, XPS spectra and single crystal X-ray diffraction analyses. The two compounds consist of 4,4′-bpy units with different polyoxometalates, α-Keggin [AsWVI11WVO40]4− and pseudo-Keggin [PMoVI9MoV3O40]6−, respectively. No direct interactions occur among polyoxoanions in these two compounds, but the clusters together with metal-organic units or organic 4,4′-bpy units and/or water molecules construct the high-dimensional supramolecular networks through hydrogen bonds. The crystal structure analyses reveal that the organic 4,4′-bpy units have a major influence on the packing arrangements of crystals.