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

Abstract

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 Na₅Fe_2.5[W₁₂O₄₀(OH)₂]·36H₂O (Na₅Fe_2.5paraB) and Na₄Cu₃[W₁₂O₄₀(OH)₂]·28H₂O (Na₄Cu₃paraB), 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 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.

Keywords: IPOT; POM; crystal structure; dodecatungstate; isopolytungstate; polyoxometalate; three-dimensional structure.