Synthesis and characterization of the first polyoxometalate possessing bicapped by antimony α-Keggin structure (C2N2H9)2[PMo5VMo7VISb2IIIO40] • 2H2O

A novel polyoxometalate (C2N2H9)(2)[(PMo5Mo7Sb2O40)-Mo-V-Sb-VI-O-III] center dot 2H(2)O (1) has been synthesized in the system of Sb2O3-(NH4)(6)Mo7O24 center dot 4H(2)O-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 [(PMo5Mo7Sb2O40)-Mo-v-Sb-VI-O-III](2-). The structure unit [(PMo5Mo7Sb2O40)-Mo-v-Sb-VI-O-III](2-) is the first example of bicapped by antimony alpha-Keggin structure. (C) 2006 Elsevier B.V. All rights reserved.