The synthesis and characterization of the 3-D framework of SO42− supported Keplerate-type polyoxometalate

We report a Keplerate-type polyoxometalate Na18K8[{Mo6O21(H2O)3(SO4)}12(Fe(H2O)2)30]·ca. 67 H2O (1), which is composed of 12 pentagonal {(Mo)Mo5} units and 30 [Fe(H2O)2]3+ linkers. This giant heterometal Keplerate-type cluster is supported by SO42− and display interesting topologies, which are connected by two kinds of Na+ cations (mononuclear and binuclear Na+ cations) to form three-dimensional (3-D) open-framework. The compound was characterized by the elemental analysis, thermogravimetry, spectroscopic methods (IR and UV/Vis), bond valence sum (BVS) calculations, X-ray photoelectron spectroscopy (XPS) and single crystal X-ray structure analysis. The photocatalytic property of compound 1 has been investigated, which shows a good photocatalyst for the degradation of RhB.