A novel Keggin-type polyoxoanion supported by copper(II) coordination cations

The title compound [Cu(DMF)3(H2O)]2[α-SiW12O40]·3H2O was synthesized in mixed solvent of water and acetonitrile by reaction of α-H4SiW12O40·nH2O, CuCO3·Cu(OH)2·xH2O and DMF. The results of X-ray diffraction analysis show that the title compound generates a neutral and discrete cluster assembled from a [α-SiW12O40]4− polyoxoanion and two [Cu(DMF)3(H2O)]2+ coordination cations. The title compound crystallizes in the monoclinic, space group C2/c, with lattice constants: a=21.260(4), b=16.720(3), c=20.160(4) Å, β=105.70(3)°, V=6899(2) Å3, Z=4, Dc=3.389 Mg/m3, F(000)=6240, R1=0.0721, wR2=0.1129.