First Strandberg-type polyoxotungstate compound: Synthesis and characterization of organic–inorganic hybrid (H2en)(Hen)2[H2P2W5O23]·5.42H2O

The first Strandberg-type polyoxotungstate compound, (H2en)(Hen)2[H2 P2W5O23]·5.42H2O (en = ethylenediamine), has been hydrothermally synthesized and characterized by single crystal X-ray diffraction, elemental analyses, IR, UV–vis spectra, thermogravimetric analyses and cyclic voltammetry measurements. It was revealed that the Strandberg-type polyoxotungstate cluster can be considered as a ring formed by five distorted edge- and corner-sharing WO6 octahedra, capped on both poles by a phosphate tetrahedron sharing three vertices with the ring tungsten centers. The Strandberg clusters are connected with the organic amines through hydrogen-bonding interactions into a three-dimensional supramolecular network.