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]·H(2)O (1·H(2)O), [Cd(4)(trz)(5)Cl(3)(H(2)O)]·(THF)(1.25)·(H(2)O)(2.5) (2·1.25THF·2.5H(2)O), [Cd(3)(trz)(2)Cl(MeCN)] (3), [Cd(3)(trz)(4)Cl(2)]·(H(2)O)(0.5) (4·0.5H(2)O), and [Cd(4)(trz)(6)Cl(2)(H(2)O)(0.5)]·(H(2)O)(3.5) (5·3.5H(2)O). 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 μ(1,2,4) bridging mode, and chloride ions display a μ(2), μ(3), μ(4) bridging mode, respectively, which makes the structural diversity in the assembling system, for example, μ(4)-Cl and cadmium triazolate, build up an unprecedented tetranuclear cluster [Cd(4)(trz)(8)Cl](-) in 2. All of the materials exhibit intense blue fluorescent emission and high thermal stability, wherein 1 presents an interesting guest-responsive photoluminescent property.