Synthesis, Crystal Structure, and Photoluminescent Properties of Ternary Cd(II)/Triazolate/Chloride System

Solvothermal reactions of cadmium chloride and 1,2,4-triazole (Htrz) in different solvent mediums have successfully synthesized five ternary Cd(II)/trz/Cl− complexes, [Cd(trz)Cl]·H2O (1·H2O), [Cd4(trz)5Cl3(H2O)]·(THF)1.25·(H2O)2.5 (2·1.25THF·2.5H2O), [Cd3(trz)2Cl(MeCN)] (3), [Cd3(trz)4Cl2]·(H2O)0.5 (4·0.5H2O), and [Cd4(trz)6Cl2(H2O)0.5]·(H2O)3.5 (5·3.5H2O). All of these five coordination polymers have three-dimensional (3-D) structural features, which are constructed by distinct substructures including clusters, chains, rings, and even 3-D frameworks. In all cases, 1,2,4-triazolate adopts a μ1,2,4 bridging mode, and chloride ions display a μ2, μ3, μ4 bridging mode, respectively, which makes the structural diversity in the assembling system, for example, μ4-Cl and cadmium triazolate, build up an unprecedented tetranuclear cluster [Cd4(trz)8Cl]− in 2. All of the materials exhibit intense blue fluorescent emission and high thermal stability, wherein 1 presents an interesting guest-responsive photoluminescent property.