Three-dimensional lanthanide metal-organic frameworks constructed from octahedral secondary building units: Pcu net topology and luminescence

Three isomorphous three-dimensional lanthanide metal–organic frameworks, [Ln2(NIPH)3(DMF)4]·(DMF)2 (Ln = Eu, Pr and Sm, and H2NIPH = 5-nitroisophthalic acid) have been synthesized under solvothermal condition and characterized by single-crystal X-ray structure diffraction, IR spectroscopy, thermogravimetric analysis (TGA), luminescent property and elemental analyses. In their structures, two lanthanide(III) ions are bridged by four carboxylate groups and chelated by another two carboxylate groups to generate a [Ln2(COO)6] dinuclear group, which serves as octahedral secondary building unit (SBU) to produce a pcu net.