Syntheses,Crystal Structures and Photoluminescence Properties of Two Cadmium(Ⅱ) Coordination Polymers

The solvothermal reaction of CdCl_2·2.5 H_2O with terephthalic acid yields two new three-dimensional(3 D) cadmium(II) coordination polymers(CPs), namely {Cd(C_8H_4O_4)Cl]·C_2H_8N}_n and Cd(C_8H_4O_4)]_n, we use the abbreviations CP1 and CP2 to refer to them, respectively. The compounds are characterized in detail by single-crystal X-ray diffraction, powder X-ray diffraction, IR spectroscopy, elemental analysis and thermogravimetric analysis(TGA). The results indicate that compounds CP1 and CP2 are 3 D frameworks, and both the compounds feature a uninodal 4-connected framework with a dia net. The empty spaces of such 3 D framework are filed by the other two identical frameworks, leading to a 3-fold interpenetrated network. In addition, the photochemical properties of the frameworks are also investigated. The two frameworks show strong solid-state fluorescence emission at 463 and 503 nm, respectively, which are obvious red-shift compared to the emission of ligand.