Two cobalt(II) coordination polymers constructed from tetrafluoroterephthalate and hexamethylenetetramine ligands

Two cobalt(II) coordination polymers, {[Co(Hmt)(2)(tfbdc)(H2O)(2)]center dot(H(2)tfbdc)center dot(EtOH)(2)}(n) (1) and {[Co(Hmt)(tfbdc)(H2O)(2)]center dot(H2O)(2)}(n) (2) (H(2)tfbdc = 2,3,5,6-tetrafluoroterephthalic acid; Hmt = hexamethylenetetramine) have been synthesized and characterized by physicochemical and spectroscopic methods, thermogravimetric analysis, and single-crystal X-ray diffraction. In both complexes, the coordination environment around cobalt is distorted octahedral. In 1, each Co(II) atom is linked by tfbdc(2-) anionic ligands to form a 1D zigzag chain, which is further connected into a 3D network via hydrogen bond interactions. In 2, each Co(II) atom is bridged by anionic tfbdc(2-) and Hmt ligands along two directions, respectively, forming an infinite 2D structure with a parallelogram-type grid; the 2D networks are further assembled to a 3D framework via intermolecular hydrogen bond interactions. Both complexes show blue fluorescence in the solid state at room temperature. Two new coordination polymers, {[Co(Hmt)(2)(tfbdc)(H2O)(2)]center dot(H(2)tfbdc)center dot(EtOH)(2)}(n) (1) and {[Co(Hmt)(tfbdc)(H2O)(2)]center dot(H2O)(2)}(n) (2) have been obtained via the reactions of H(2)tfbdc, Hmt, and cobalt chloride hexahydrate in different molar ratios and solvents.