catena-Poly[[[tetraaquacobalt(II)]-μ-4,4′-bipyridine-κ2N:N′] 1,2-phenylenedioxydiacetate 4,4′-bipyridine hemisolvate dihydrate]

In the title compound, {[Co(C10H8N2)(H2O)(4)](C10H8O6)center dot-0.5C(10)H(8)N(2)center dot 2H(2)O}(n), the Co atoms are bridged into a chain by 4,4'-bipyridine units; both the bridging and the uncoordinated 4,4'-bipyridine molecules are arranged around inversion centres and are centrosymmetric. Two-dimensional 'fishingnet' layers are built up through O-H center dot center dot center dot N hydrogen-bond interactions. The diacid anions and uncoordinated water molecules fill the space between the layers. A three-dimensional supramolecular network is built up by O-H center dot center dot center dot O and O-H center dot center dot center dot N hydrogen-bond interactions between water molecules, anions and 4,4'-bipyridine molecules.