Synthesis, structure and luminescent properties of two-dimensional lanthanum(III) porous coordination polymer based on pyridine-2,6-dicarboxylic acid

The novel porous coordination polymer {[La4(PDA)10(H2O)8]·2H2O}n with two-dimensional framework has been prepared by hydrothermal synthesis of pyridine-2,6-dicarboxylic acid (H2PDA) and lanthanum nitrate under mild conditions and characterized by elemental analyses, IR spectroscopy, thermal analyses and single crystal X-ray diffraction. The complex crystallizes in triclinic system, space group P-1. La(III) ions in the coordination polymer are nine-coordinated and have N1O8 or N2O7 polyhedral units connected to the PDA2− anions forming tricapped trigonal prism geometries. The H2PDA ligands coordinate to the central La(III) ions in bridging tetradentate and pentadentate modes. The thermal decomposition of the complex has been predicted with the help of thermal analyses (TG and DTG). The complex exhibits luminescent property in the near-UV at room temperature in the solution of DMSO due to the π* → n or π* → π transitions of PDA2− anions.