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A new bicapped Keggin heteropolyoxoanion derivative [Co(bpy) 3 ] 2 [V IV O 40 (V IV O) 2 ] [{Co(bpy) 2 (H 2 O)} 2 {V IV O 40 (V IV O) 2 }]  ·  8H 2 O (1) (bpy  =  2,2′-bipyridine), has been hydrothermally synthesized and structurally characterized by elemental analysis, single crystal X-ray diffraction, IR and X-ray photoelectron spectra. Complex 1 consists of two [Co(bpy) 3 ] 2+ cations, an anion of [V IV O 40 (V IV O) 2 ] 4- and a neutral unit [{Co(bpy) 2 (H 2 O)} 2 {V IV O 40 (V IV O) 2 }] in which {V IV O 40 (V IV O) 2 } 4- is coordinated to two Co atoms through its terminal oxygen atoms of the two capping V atoms at opposite sites together with bipyridine and water ligands. The most interesting feature of 1 is that a polyoxoanion and a neutral component coexist in the crystal structure. Hydrogen-bonding contacts are also formed between different polyanions through the lattice water molecules. [ABSTRACT FROM AUTHOR]

A hydrothermal reaction of WO3, CoCl2 and 4,4′-bipyridine, yields a novel organic–inorganic hybrid compound, Co2(bpy)6(W6O19)2, at 170°C. X-ray single crystal structure determination reveals a two-dimensional covalent structure belonging to monoclinic crystal system, space group C2/c, with cell parameters a=19.971(4) Å, b=11.523(2) Å, c=16.138(3) Å, β=96.49(3)°, V=3690.0 Å3 and Z=2. The hexatungstate, [W6O19]2-, acts as a building block in bidentate fashion to bridge the Co(II) centers in the crystal structure. The title compound is found to have an optical energy gap of 2.2 eV from UV–Vis–NIR reflectance spectra. [Copyright &y& Elsevier]