A novel extended architecture with 46·64 topology based on mixed-valence Wells–Dawson arsenotungstate and mixed-ligand Cu(I) units

A novel inorganic–organic hybrid compound based on mixed-valence Wells–Dawson arsenotungstate and mixed-ligand Cu(I) units, Cu8I(imi)4(bpy)6(H2O)[As2VW2VW16VlO62]·2H2O (1) (bpy=4,4′-bipydine; imi=imidazole), has been hydrothermally synthesized and characterized by elemental analysis, IR spectroscopy, thermal gravimetric analysis, luminescent spectrum and single crystal X-ray diffraction. Single-crystal X-ray diffraction revealed that four terminal and three bridging oxygen atoms of the Wells–Dawson cluster are coordinated to Cu(I) ions and form an unprecedented hepta-supporting polyoxometalate. The functionalized arsenotungstates are further connected by two kinds of tridentate linkers, Imi–Cu–(bpy)–Cu–(bpy)–Cu–(bpy)–Cu–Imi and Imi–Cu–(bpy)–Cu–(bpy)–Cu–H2O, to construct a 3D framework with 46·64 topology. The hybrid material has an intense emission at about 397 nm.