Five 3D lanthanide-based coordination polymers with 3,3,6T13 topology: Structures and luminescent sensor for Hg2+ and Pb2+ ions

A series of isostructural lanthanide coordination polymers Ln-CPs, {[Ln(2)(PBA)(3)(H2O)(3)]center dot DMF center dot 3H(2)O}(n)(Ln = La 1, Nd 2, Sm 3, Eu 4, Dy 5), based on a tripodal nitrogen-containing carboxylic ligand (H(2)PBA=5-(4-pyridin-3-yl-benzoylamino)-isophthalic acid), have been successfully synthesized under solvothermal conditions. Structural analyses show that compounds 1-5 are isomorphous and crystallize in triclinic space group and feature an interesting 3,3,6T13 network topology with point symbol (4.5(2))(2)(4(2).5(2).10.6.7(2))(5(8).6(4).10.6.7(2)). There exist two kinds of 1D metal-carboxylate chains, which are further extended into 3D framework through the connection of PBA(2-) ligands. Moreover, luminescent spectra of compound 4 are also investigated in visible region, which indicates that it could be used to detect toxic metal cations with relatively high sensitivity and selectivity towards Hg2+ and Pb2+ in DMF solvent.