Influence of solvent on the structures of two one-dimensional cobalt(II) coordination polymers with tetrachloroterephthalate

The title cobalt coordination polymers, catena-poly[[[aqua-tripyridinecobalt(II)]-mu-tetrachloroterephthalato] pyridine solvate],{[ Co(C(8)Cl(4)O(4))(C(5)H(5)N)(3)(H(2)O)]center dot C(5)H(5)N}n, (I), and catena-poly[[[diaquadipyridinecobalt(II)]-mu-tetrachloroterephthalato] 1,4-dioxane trihydrate], {[Co(C(8)Cl(4)O(4))(C(5)H(5)N)(2)(H(2)O)(2)]center dot C(4)H(8)O(2)center dot 3H(2)O}(n), (II), have been prepared with tetrachloroterephthalic acid (H(2)BDC-Cl(4)) under different solvent media. Both complexes form infinite cobalt(II)-tetrachloroterephthalate polymeric chains. In (I), two independent Co(II) ions are six-coordinated through N(3)O(3) donor sets in slightly distorted octahedral geometries provided by two carboxylate and three pyridine ligands, and one water molecule. The structure of (II) contains two independent Co II atoms, each lying on a twofold axis, which adopt a tetragonally distorted N(2)O(4) octahedral geometry via two carboxylate groups, two pyridine ligands and two water molecules. The different stoichiometry of coordinated and solvent guest molecules leads to different two-dimensional supramolecular networks, with (I) utilizing C-H center dot center dot center dot pi and weak pi-pi interactions and (II) utilizing mainly conventional hydrogen bonding.