Hydrothermal syntheses, characterizations and crystal structures of 1-D and 2-D arsenotungstates based on Dawson-type units

Two arsenotungstates based on Dawson polyanions, 1-D chain H8[{CuI(en)2}4{CuI(2,2′-bipy)(H2O)}2{CuI(2,2′-bipy)(As2W17CuO61)}2] · 4H2O (1) and 2-D network [Cu(2,2′-bipy)3]2 [(As2W18O62)Na4(H2O)11]2 · 7H2O (2) (2,2′-bipy = 2,2′-bipyridine), have been hydrothermally synthesized and characterized by elemental analyses, IR, ESR, TG-DTA and single-crystal X-ray diffraction. Compound 1 crystallizes in triclinic system, space group P−1, a = 11.640(3), b = 13.177(3), c = 31.143(7) Å, α = 87.43(0)°, β = 84.47(0)°, γ = 68.02(0)°. Compound 2 crystallizes in hexagonal system, space group P−6 2c, with a = 12.9175(7), c = 28.371(3) Å. The structure of 1 represents the first 1-D chain consisted of oxo-bridged Wells–Dawson arsenotungstate anions. The compound 2 is the first 2-D sodium arsenotungstate, whose building units [(As2W18O62)(H2O)8Na2]4− were connected to neighboring units via [Na2(H2O)3]2+ bridging groups.