Extended Network via π…π Interaction and Hydrogen Bond Linkages of 1D Copper(II) Coordination Polymer: Synthesis, Crystal Structure and Characterization of [Cu(4,4'-bpy) (2-pzc)-(H_2O)]ClO_4·H_2O (2-pzc = 2-pyrazine-5-carboxylate; 4,4'-bpy = 4, 4

摘要

A penta-coordinated Cu(II) complex with mixed ligands 4,4'-bipyridine (4,4'-bpy) and 2-pyrazine-5-carboxylate anion (2-pzc), [Cu(4,4'-bpy)(2-pzc)(H_2O)]ClO_4·H_2O (1), has been solvothermally synthesized and characterized. Complex 1 crystallizes in the monoclinic space group P2_1 with a = 0.82996(2) nm, b = 1.58156(5) nm, c = 1.53837(1) nm, = 103.536(2)°, V = 1.96322(8) nm~3, M_r = 478.30, Z = 4, D_c = 1.618 g/cm~3, final R = 0.0544 and wR = 0.1487. The Structure of 1 indicates that the central Cu(II) atom is penta-coordinated by two N atoms from two 4,4'-bpy ligands, and one N atom and one oxygen atom of the 2-pzc ligand in the equatorial plane, and one oxygen atom of the coordinated water molecule at the axial position. The coordination geometry of Cu(II) atom could be considered as a slightly distorted square-pyramidal environment. The 4,4'-bpy ligands bridge the Cu(II) centers to form a one-dimensional chain, and 2-pzc acts as a terminal chelated ligand, and π…π interaction between the pyrazine rings of 2-pzc ligands of adjacent chains links the chains into a 2D sheet. Furthermore, the hydrogen bonds among the oxygen atoms of the uncoordinated water molecules and the N atoms and O atoms of 2-pzc ligands and the oxygen atoms of the coordinated water molecules link the sheets into the ultimate 3D network of complex 1.