Coordination polymers with bis(2-benzimidazole) ligand as bridging ligand: From 1D chain to 3D microporous structure

Three coordination polymers, i.e. [Co(HL)(HBDC)]n (1), [Co(HL)(BDC)0.5]n (2) and {[Zn2(H2L)(BTC)2](H4L)(H2O)2}n (3) (L = 2, 2′-(ethanediyl)bis(1H-benzimidazole), H2BDC = 1, 4-benzenedicarboxylic acid, H3BTC = 1, 3, 5-benzene tricarboxylic acid), have been synthesized under hydrothermal conditions based on bis(2-benzimidazole) and two multi-dentate carboxylate ligands, with different metal ions such as ZnII and CoII. The structures of these coordination polymers have been determined by X-ray single‐crystal diffraction. The diverse coordination modes of the H2L ligand and the varying geometries of multi-dentate carboxylate ligands play an important role in the construction of coordination polymers. Various assembly patterns have been observed, including one-dimensional (1D) chain (1), two-dimensional (2D) 3-connected network structure with honeycomb topology (2), and three-dimensional (3D) 3,4-connected porous structure with (63)(65,8) topology (3). Thermal analyses of the three polymers have been performed and discussed. Furthermore, strong room temperature photoluminescence of compound 3 was observed.

Three new metal–organic frameworks based on the bis(2-benzimidazole), [Co(HL)(HBDC)]n (1), [Co(HL)(BDC)0.5]n (2) and {[Zn2(H2L)(BTC)2](H4L)(H2O)2}n (3), have been successfully synthesized under hydrothermal conditions and characterized by X-ray single-crystal diffractions. In addition, strong photoluminescence at room temperature of compound 3 was observed at room temperature.Figure optionsDownload as PowerPoint slideHighlights
► Compound 1 shows a 1D chain architecture with L ligand hanging outside the chain structure.
► Compound 2 exhibits a 2D extra-large 32-membered ring network with honeycomb topology.
► Compound 3 exhibits a 3D 3, 4-connected porous structure with (63)(65,8) topology.