Two cadmium(II) coordination polymers constructed from dicarboxylate and bis(imidazole) ligands: Syntheses, crystal structures, luminescence and photocatalytic properties

Abstract

Two cadmium(II) coordination polymers, namely Cd4(DPA)4(BIMB)2·H2O (1) and Cd2(DPA)2(FBIMB)2·H2O (2), where H2DPA=diphenic acid, BIMB=1,4-bis(imidazol-1-yl-methyl)benzene and FBIMB=2,3,5,6-tetrafluoro-1,4-bis(imidazol-1-yl-methyl)benzene, have been synthesized under hydrothermal conditions and characterized by IR, elemental analyses and single crystal X-ray diffraction. Structural analyses reveal that complex 1 features a two-dimensional (2D) layer structure based on one-dimensional (1D) Cd-DPA chains, while complex 2 exhibits an interesting three-dimensional (3D) 4-connected network with (65.8) topology. A careful structural comparison reveals that the similarity of the Cd(II) coordination geometry and ligand binding mode, but the significant discrepancy of their network, which may be attributed to the fluorinated substituent group. Two complexes indicate high thermal stabilities and different photoluminescence behavior in the solid state. Moreover, two complexes present good photocatalytic activities in methylene blue (MB) degradation reactions.