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

Abstract A novel polyoxometalate ( C 2 N 2 H 9 ) 2 [ PMo 5 V Mo 7 VI Sb 2 III O 40 ] · 2 H 2 O ( 1 ) has been synthesized in the system of Sb 2 O 3 -(NH 4 ) 6 Mo 7 O 24  · 4H 2 O-H 3 PO 4 -en-H 2 O 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 (H 2 O) 2 ] 2+ and two-dimensional layer formed by [ PMo 5 V Mo 7 VI Sb 2 III O 40 ] 2 - . The structure unit [ PMo 5 V Mo 7 VI Sb 2 III O 40 ] 2 - is the first example of bicapped by antimony α-Keggin structure.