Synthesis, Characterization, and Photoluminescence of Lanthanide-containing Coordination Polymers Constructed from 4,4′-Biphenyldicarboxylate and 2,4,6-Tris(2-pyridyl)-1,3,5-triazine Ligands

Six isomorphous metal- organic frameworks: Ln(2)(bpdc)(3)(tptz)(2)(H2O)center dot 3DMA center dot 7H(2)O [Ln(3+) = Nd3+ (1), Sm3+ (2), Eu3+ (3), Gd3+ (4), Tb3+ (5), Dy3+ (6)] [bpdc(2-) = 4,4'-biphenyldicarboxylate, tptz = 2,4,6-tris(2-pyridyl)-1,3,5-triazine, DMA = N,N-dimethylacetamide], were synthesized by the self-assembly of lanthanide ions, bpdc(2-), tptz, DMA, and H2O. Single-crystal X-ray diffraction reveals that all compounds are 1D coordination polymers with pi-pi interactions via tptz among adjacent chains, forming a 3D supramolecular network. Compounds 2, 5, and 6 exhibit mainly ligand luminescence, whereas 3 exhibits intense characteristic Eu3+ emissions at room temperature.