Crystal structure of poly[[μ₃-4,4′-(4,4′-bipyridine-2,6-diyl)dibenzoato]{μ₂-4-[6-(4-carboxyphenyl)-4,4′-bipyridin-4′-ium-2-yl]benzoato}manganese(II)] hemi­hydrate]

The title compound, {[Mn(C₂₄H₁₄N₂O₄)(C₂₄H₁₆N₂O₄)]·0.5H₂O}_n, was obtained by the reaction of manganese nitrate with the ligand 4,4′-(4,4′-bi­pyridine-2,6-di­yl) di­benzoic acid under hydro­thermal conditions. The water O atom is located on a twofold rotation axis. The Mn²⁺ ion is hepta­coordinated by six O atoms and one N atom from the ligands. In this structure, the ligands adopts two different forms, one completely deprotonated and one with a protonated N atom (pyridinium) and a carboxylic acid function. In the crystal, N—H...O and O—H...O hydrogen bonds consolidate the packing, forming a three-dimensional framework.