Hydrogen-bonded supramolecule of N,N'-bis(4-pyridylmethyl)oxalamide and a zigzag chain structure of catena-poly[[[dichloridocobalt(II)]-mu-N,N'-bis(4-pyridylmethyl)oxalamide-kappa2N4:N4'] hemihydrate].

N,N'-Bis(4-pyridylmethyl)oxalamide, C(14)H(14)N(4)O(2), exists as a dimer which is extended into a two-dimensional network with other dimers through pyridine-amide hydrogen bonds. The crystal structure of the title coordination polymer, {[CoCl2(C(14)H(14)N(4)O(2))].0.5H2O}n, features a one-dimensional zigzag chain, in which the cobalt ion sits at a twofold symmetry position and adopts a tetrahedral geometry, and the bridging ligand lies on an inversion center and connects to Co(II) ions in a bis-monodentate mode. Furthermore, two interwoven chains create a cavity of ca 8.6 x 8.6 A, which produces a three-dimensional channel. Water molecules are held in the channel by hydrogen bonds.