Acta Cryst. (2014). E70, m4-m5 [ doi:10.1107/S1600536813032297 ]
Abstract: In the title polymeric compound, [Cu(C8H5O3)2(C4H4N2)(H2O)2]n, the CuII atom is located on a twofold rotation axis and has a slightly distorted octahedral coordination sphere. In the equatorial plane, it is coordinated by two carboxylate O atoms of two symmetry-related monodentate formylbenzoate anions and by two N atoms of the bridging pyrazine ligand, which is bisected by the twofold rotation axis. The axial positions are occupied by two O atoms of the coordinating water molecules. In the formylbenzoate anion, the carboxylate group is twisted away from the attached benzene ring by 6.2 (2)°, while the benzene and pyrazine rings are oriented at a dihedral angle of 68.91 (8)°. The pyrazine ligands bridge the CuII cations, forming polymeric chains running along the b-axis direction. Strong intramolecular O-HO hydrogen bonds link the water molecules to the carboxylate O atoms. In the crystal, O-HwaterOwater hydrogen bonds link adjacent chains into layers parallel to the bc plane. The layers are linked via C-HpyrazineOformyl hydrogen bonds, forming a three-dimensional network. There are also weak C-H interactions present.
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