Double-Keggin-type Anion-templated Synthesis of a 3D Porous Coordination Polymer of Eu(III) Ions and dpdo Ligands

A porous coordination polymer, {[Eu(dpdo)4(H2O)3]H(SiMo12O40)(dpdo)0.5(CH3CN)0.5(H2O)4}n (1), (where dpdo is 4,4′-bipyridine-N,N′-dioxide) templated by double-Keggin-type polyanions has been synthesized through the self-assembly of Eu(III) ions and dpdo in acetonitrile/water solution and structurally characterized by elemental analysis, IR spectra and single crystal X-ray diffraction. The X-ray structure analysis reveals that compound 1 exhibits a 3D non-interwoven framework with large cavities housing centro-symmetrically related shoulder-by-shoulder double-Keggin anions as guests. The result of a thermogravimetric analysis suggests that the metal-organic framework has high thermal stability.