A six-connected 3-D framework [enH2]2[Cu(en)2]3[H2W12O42]·6H2O constructed from paratungstate-based polyoxometalate units

An organic–inorganic hybrid paratungstate [enH2]2[Cu(en)2]3[H2W12O42]·6H2O (1) (en = ethylenediamine) has been hydrothermally synthesized by reaction of Na2WO4·2H2O with CuCl2·2H2O in the presence of en and structurally characterized by elemental analyses, IR spectroscopy, UV spectrum, powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA) and X-ray single-crystal diffraction. It is worth pointing out that 1 exhibits the 6-connected 3-D framework with the long topological (OʹKeeffe) vertex symbol 4·4·64·4·4·4·4·64·4·4·4·64·4·4·4 for the [Cu(en)2]3[H2W12O42]4 − node, which gives the short vertex (Schläfli) symbol of 41263. To the best of our knowledge, such 6-connected 3-D open-framework constructed from paratungstate clusters is for the first time observed in polyoxometalate chemistry.