A New Zn(II) Two-dimensional Coordination Polymer: Synthesis, Structure, Highly Efficient Fluorescence and DFT Study.

A new two-dimensional coordinate polymer, {[Zn2(pbmpd)(H2O)4]·(H2O)}n (H4pbmpd = 1,1'-(1,4-phenylenebis(methylene))bis-(1H-pyrazole-3,5-dicarboxylic acid)), has been hydrothermally synthesized and characterized by IR spectrum, elemental analysis，TGA and X-ray single-crystal/powder diffraction. Structural analyses reveal that complex 1 exhibits a two-dimensional sheet structure in the crystal lattice. In complex 1, the carboxylic oxygen atoms and conjugated N atoms of pbmpd4- bridge zinc(II) ions form indefinitely zigzag shaped one-dimensional chains through p···p stacking interactions which are further connected by [ZnO6] units to form a novel two-dimensional structure. Finally, p···p stacking interactions and intermolecular hydrogen bonds assemble the two dimensional networks into a three-dimensional framework. Furthermore, the luminescent properties are also discussed. Interestingly, the solid state photoluminescence properties of the title polymer show the enhancement effect of spectrum. Density functional theory (DFT) calculations were used to support the experimental data.