Iron(II) and copper(II) paratungstates B: a single-crystal X-ray diffraction study

Paratungstate B is a common isopolytungstate (IPOT) built of the [W12O40(OH)(2)](10-) anion and exhibits a cluster-like construction of 12 W-centred distorted octahedra. Due to a high surface charge density, the paratungstate anion acts as a multidentate ligand forming high-dimensional extended structures, which exhibit unique catalytic and magnetic properties. Two new paradodecatungstate B compounds decorated by iron(II) or copper(II), namely Na5Fe2.5[W12O40(OH)(2)]center dot 36H(2)O (Na(5)Fe(2.5)paraB) and Na4Cu3[W12O40(OH)(2)]center dot 28H(2)O (Na(4)Cu(3)paraB), have been synthesized by a convenient aqueous solution method, and structurally characterized by single-crystal and powder X-ray diffraction, IR spectroscopy, elemental analysis and thermogravimetric analysis. Both compounds crystallize in the triclinic P (1) over bar space group. In both compounds, the [W12O40(OH)(2)](10-) polyanion acts as a multidentate ligand that links transition-metal and sodium cations, forming a three-dimensional framework.