Crystal structure of catena-poly[[diaquabis(4-formylbenzoato-κO1)cobalt(II)]-μ-pyrazine-κ2N:N′]

In the title polymeric compound, [Co(C8H5O3)2(C4H4N2)(H2O)2]n, the CoII 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 two bridging pyrazine ligands. The latter are 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 7.50 (8)°, while the benzene and pyrazine rings are oriented at a dihedral angle of 64.90 (4)°. The pyrazine ligands bridge the CoII cations, forming linear chains running along the b-axis direction. Strong intramolecular O—H...O hydrogen bonds link the water molecules to the carboxylate O atoms. In the crystal, weak O—Hwater...Owater hydrogen bonds link adjacent chains into layers parallel to the bc plane. The layers are linked via C—Hpyrazine...Oformyl hydrogen bonds, forming a three-dimensional network. There are also weak C—H...π interactions present