Two novel 2D and 3D coordination polymers constructed from pyrazine-2,3-dicarboxylic acid and chloride bridged secondary building units

Abstract

The synthesis, spectroscopic properties and crystal structures of {[Cu-2(mu-Cl)(2)(mu(3)-Hpzdc)(Cl)(H2O)(2)]center dot 1.5H(2)O}(n) (1) and {[Cd(mu-Cl)(mu-Hpzdc)]center dot H2O)}(n) (2) complexes were reported (H(2)pzdc = pyrazine-2,3-dicarboxylic acid). H(2)pzdc is singly deprotonated in both complexes and the coordination mode of Hpzdc ligand in 1 has been first reported in this presentation. The complex 1, which has a 3D framework structure, was formed with double mu-chloride and mu(3)-Hpzdc bridges. In 1, water molecules occupy in the 1D channel as guest molecules. Furthermore, unprecedented 1D hybrid water-chloride anionic [(H2O)(8)Cl-2](n) cluster has been structurally identified. In the complex 2, the Cd(II) atom is seven-coordinated by two hydrogen pyrazine-2,3-dicarboxylate, two chloride and one aqua ligands in a distorted monocapped octahedral coordination geometry. The Cd(II) atoms are bridged by the bis(bidentate) Hpzdc ligands, forming 1D polymer chain. The adjacent 10 chains are linked each other through the double chloride bridges to form 20 layer. The layers are connected together through O-H center dot center dot center dot O interactions resulting in a three-dimensional framework. The mechanisms for these compounds were validated by density functional theory (DFT) calculations on the experimental geometries. The photoluminescent property of 2 was investigated in the solid state at room temperature. Moreover, in order to assess the potentials of 1 and 2 in gas storage applications, we performed atomically detailed simulations.