Structures and Properties of Two New Three-Dimensional Inorganic-Organic Hybrid Compounds Based on Isopolymolybdate Clusters

Two new inorganic-organic hybrid materials containing different isopolymolybdate units, namely, [{Ce（pdca）（H20）} {Ce（pdca）（H20）5}]2{MosO26}o10H2O （1）, [Cu（phen）（HzO）2]2[Mo6O20] （2） （pdca=pyridine-2,6- dicarboxylic acid, phen= 1,10-phenanthroline） have been successfully synthesized under hydrothermal conditions, and characterized by elemental analyses, IR spectra, thermal gravimetric analyses （TGA）, single-crystal X-ray diffraction and powder X-ray diffraction （PXRD）. In compound 1, Ce（III） ions are bridged by pdca ligands to form ce- rium-organic coordination layers, which are further pillared by octamolybdate clusters via the covalent bonding of Ce--O, leading to the formation of a 3D pillar-layered open-framework architecture. Compound 2 features a 3D supramolecular structure constructed by hydrogen bond interactions between 1D molybdate chains aggregated by [M06020]4- polyoxoanions and coordinated water molecules. It was remarkable that H3[PMol2040]·XH20 decomposes into hexamolybdate anions, which are linked together with phen ligands by Cu（II） cation. Moreover, UV-vis spectra and fluorescence properties of compounds 1- 2 have also been investigated in detail.