Two Cadmium-Cluster-Based Metal–Organic Frameworks with Mixed Ligands of 1,2,3-Benzenetriazole (HBTA) and 1,4-Benzenedicarboxylic acid (H₂BDC)

Abstract

Two cadmium(II) metal–organic frameworks based on two mixed ligands of HBTA and H2BDC, [Cd5(BTA)6(BDC)2(DMF)4(H2O)2]n·n(2DMF·H2O) (1) and [Cd7(BTA)2(BDC)6(DMF)8]n·2nDMF (2) (HBTA = 1,2,3-benzenetriazole; H2BDC = 1,4-benzenedicarboxylic acid), have been prepared through methods of liquid to liquid diffusion and solvothermal reaction, respectively. The results of single-crystal X-ray diffraction analyses indicate that both MOFs are constructed from cadmium clusters. In 1, six BTA– anions connect five Cd(II) ions to generate a tetrahedral Cd5 cluster, which further links with four equivalent Cd5 clusters through four BDC2– bridges, forming a (4,4)-connected two–dimensional (2D) layer structure. In 2, each BTA– anion connects three Cd(II) ions to generate a triangular Cd3 cluster, which further links with four Cd3 clusters and two 3-connected BDC2– anions, forming a (3,6)-connected three-dimensional (3D) framework. The results of photoluminescent measurements illustrate that in the solid state, both 1 and 2 can emit fluorescence at 465 and 450 nm, respectively.