Crystal Structure and Characterization of a Novel 2D Layered Compound Assembled from Paradodecatungstate Clusters

A novel 2D layered compound （H4HMTA）2（H3O）2{Na2（H2O）6（H2W12O42） }C12-11H2O （HMTA = hexamethylenetetraamine） has been synthesized and characterized by elemental analyses, IR, UV-Vis and X-ray diffraction. C12H74CI2N8Na2O61W12 （Mr = 3629.87） crystallizes in the triclinic system, space group P1 with a = 10.5518（2）, b = 12.1837（2）, c = 14.3088（2） A, α = 112.9470（10）, β = 93.1310（10）, γ= 106.1530（10）°, V = 1599.20（5）A3 Dc = 3.769 g.cm^-3, Z = 1, μ（MoKα） = 21.705 mm^-1, F（000） = 1634, the final R = 0.0287 and wR = 0.0686 for 5846 observed reflections with I 〉 2σ（I）. The 2D layered network is assembled from paradodecatungstate clusters linked by simple sodium-oxo bridging groups. The compound exhibits electrocatalytic activities toward both reduction and oxidation of nitrite.     

Synthesis,Structure and Characterization of [Cu(2,2′-bpy)_2][{Cu(2,2′-bpy)_2}_2W_(12)O_(40)(H_2)]·4H_2O

An organic-inorganic compound [Cu(2,2′-bpy)2][{Cu(2,2′-bpy)2}2W12O40(H2)]·4H2O (Mr = 4048.00) was prepared from the hydrothermal reaction of Na2WO4·2H2O, CuCl2·2H2O, 2,2′-bipyridine (2,2′-bpy) and H2O at 160 ℃ for 4 days. The compound crystallizes in the monoclinic system, space group P21/n with a = 18.9196(8), b = 20.4212(8), c = 21.8129(9) , β = 96.992(3)°, V = 8365.0(6) 3, Dc = 3.214 g/cm3, Z = 4, μ(MoKα) = 17.269 mm-1 and F(000) = 7324. Of the 119837 total reflections, 17315 were unique (Rint = 0.0489). The final R = 0.0385 and wR = 0.0770 for 11142 observed reflections with I > 2σ(I). Single-crystal X-ray diffraction reveals that the structure is composed of [{Cu(2,2′-bpy)2}2W12O40(H2)]2- anions, discrete [Cu(2,2′-bpy)2]2+ cations and lattice water molecules, and the anion is made up of a {W12O40(H2)}6- α-Keggin core decorated with two {Cu(2,2′-bpy)2}2+ groups through bridging oxygen atoms.