Hydrothermal syntheses and characterizations of two compounds assembled from tungstates and bpy (bpy = 4,4′-bipyridine)

Two compounds based on polyoxometalates, (4,4′-H2bpy)7(4,4′-Hbpy)[ ]2[ ] ·10H2O (1) and (4,4′-H2bpy)6(4,4′-bpy)[ ]2 · 18H2O (2), have been prepared under hydrothermal conditions and characterized by IR, XPS spectra, TG analyses, and single crystal X-ray diffraction. Both compounds consist of 4,4′-bipyridine units and polyoxometalates: [ ]5− for 1 and [ ]6− for 2. In addition, 1 contains both Keggin-type and disordered Keggin-type anions, while 2 contains a (H2O)10 water cluster.