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 H 2 BDC, [Cd 5 (BTA) 6 (BDC) 2 (DMF) 4 (H 2 O) 2 ] n · n (2DMF·H 2 O) ( 1 ) and [Cd 7 (BTA) 2 (BDC) 6 (DMF) 8 ] n ·2 n DMF ( 2 ) (HBTA = 1,2,3-benzenetriazole; H 2 BDC = 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 Cd 5 cluster, which further links with four equivalent Cd 5 clusters through four BDC 2– 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 Cd 3 cluster, which further links with four Cd 3 clusters and two 3-connected BDC 2– 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.