Synthesis, structure and luminescent properties of neodymium(III) coordination polymers with 2,3-pyrazinedicarboxylic acid

The coordination polymer [Nd2(pzdc)3(H2O)]n·nH2O (complex I) with three-dimensional framework has been prepared by hydrothermal synthesis of 2,3-pyrazinedicarboxylic acid (pzdc) and neodymium nitrate and characterized by elemental analyses, IR spectroscopy, thermal analyses and single crystal X-ray diffraction. The complex crystallizes in monoclinic system, space group P2(1)/c. Every Nd(III) atom in the coordination polymer is nine-coordinated with different coordination environments. The pzdc ligands coordinate to the central Nd(III) atoms in bridging tetradentate, hexadentate, or heptadentate modes. The thermal decomposition of the complex has been predicted with the help of thermal analyses (TG, DTG and DTA). Complex I exhibits luminescent emissions bands in the solid state at room temperature. The isomorphous complex [Nd4(pzdc)6(H2O)2]n·3nH2O (complex II) has also been prepared by hydrothermal reaction under different conditions. Luminescent emission of complex I display selectivity for some heavy metal ions.