Syntheses, structures and adsorption properties of 2D rare earth metal organic networks based on Keggin type polyoxometalate as bidentate ligand

Abstract Two Keggin-type polyoxometalates (POMs)-based rare-earth metal–organic networks, namely, [CeIV (BPDO)3(H2O)3][SiW12O40] (1, CCDC 1981416) and [PrIII(BPDO)3(H2O)3]H[SiW12O40] (2, CCDC 1981407) have been synthesized under mild hydrothermal condition (160 °C for 72 h) in the presence of 4,4′-bipyridine-N-dioxide (BPDO) ligand and Keggin-anions [SiW12O40]4−. Both compounds exhibit similar 2D layer structures constructing by typically saturated Keggin-anions [SiW12O40]4− as bidentate bridging ligand, in spite of the large steric hindrance. Our work definitely provides a new possibility to access intricate topologies, especially in highly connected networks. In addition, the adsorption properties of the compounds have been primarily investigated. From the point view of equilibrium time (