Synthesis and characterization of the first polyoxometalate possessing bicapped by antimony α-Keggin structure

A novel polyoxometalate image (1) has been synthesized in the system of Sb2O3-(NH4)6Mo7O24 · 4H2O-H3PO4-en-H2O under hydrothermal conditions and characterized by IR, TGA, elemental analyses, single crystal X-ray diffraction and XPS. Interestingly, compound 1 displays three-dimensional network consisting of one-dimensional sinusoidal chain [(Hen)2(H2O)2]2+ and two-dimensional layer formed by image. The structure unit image is the first example of bicapped by antimony α-Keggin structure.