Two New Tetranuclear Cluster-based Coordination Polymers based on Isomorphic Semi-rigid Tetracarboxylate Ligands: Syntheses,Structures, and Luminescent Properties

Two new tetranuclear cluster-based compounds, namely Cd₂(L1)(H₂O)(DMA)]_n ( 1 ) and Cd₂Ba₂(L2)(H₂O)₆(DMA)]_n ( 2 ) H₄L1 = 3-(3',5'-dicarboxylphenoxy) phthalic acid, H₄L2 = 6-(3',4'-dicarboxyl-phenoxy) isophthalic acid, DMA = N,N'-dimethylacetamide], were successfully synthesized under solvothermal conditions and structurally characterized by single-crystal X-ray diffraction analyses. Compound 1 features a two-dimensional (2D) layered framework with tetranuclear Cd₄(COO)₆] clusters as building subunits, and can be simplified into a binodal (3, 6)-connected kgd topological network with the schläfli symbol of {4³}₂{4⁶;6⁶;8³}, and compound 2 features a three-dimensional (3D) complicated framework based on heterometallic tetranulear Cd₂Ba₂(COO)₈] cluster subunits, and can be simplified into a binodal (3, 6)-connected topological network. In addition, compounds 1 and 2 not only have high thermal stabilities but also show strong luminescent emissions at room temperature.