Synthesis And Characterization Of Coordination Polymers Constructed By Novel N-and O-Containing Ligands

Crystal engineering of coordination polymer is a kind of efficient measure to design andsynthesis metal-organic framework (MOFs) featuring elegant topological structures and potentialapplications. Considering the important influence on the structures of coordination polymer, designand select suitable organic ligands are vital to construct the target complexes rationally.Four bis(benzimidazole) and bis(imidazole) ligands were successfully synthesized. By usingthose N-containing ligands and auxiliary multidentate carboxylates as mix-ligands, ten novel metal-organic coordination polymers were hydrothermally synthesized. All the crystal structures werecharacterized by single-crystal X-ray diffraction studies, infrared spectra (IR), powder X-raydiffraction (PXRD), and elemental analysis. The systematic investigation of the effect of different N-containing ligands, different metal ions and different carboxylic acids on the ultimate structures ofthese complexes are represented and discussed detailedly. The thermal stability, fluorescence andcatalytic properties of these complexes are also investigated.1) Six new complexes have been synthesized by bis(5,6-dimethylbenzimidazole) ligands (L1andL2), carboxylates and Co(II)/Ni(II) salts. Compound1displays a2D3,4L13topological layer.Complex2exhibits a1D zigzag chain. Complex3has a2D (6,3) network. Complex4shows the firstexample of3D sra topology with3-fold interpenetration in Co(II) coordination frameworks. Complex5is a1D robbin-like chain. Complex6possesses a2D undulant (6,3) net. In addition, compounds2,3and5are further extended into a high dimensional architectures by hydrogen bonds or π-πinteractions.2) Four new coordination complexes have been synthesized by the reactions of Co(II) or Cu(II)salts with dicarboxylates in the presence of bis(imidazole) mix-ligands (L3and L4). Complex7showsa2D uninodal (4,4) layer with Co(II) as node; complex8exhibits the fist2D (4,4) net withpentanuclear Cu(II) cluster as node; complex9shows the first3D α-Po net based on an unusualhexanuclear Cu(II) cluster; complex10exhibits a3-fold interpenetrated2D (4,4) net.Structure analysis shows that N-containing ligand plays a leading role in the complexes assembly,carboxylic acids and metal ions also have important influence on the structure of complexes. Thermalstability analysis shows the framework of complexes1~10exhibit high thermal stability. Complexes1~7all display good photoluminescent properties which may have potential applications asfluorescent materials. Catalytic experiment shows that compounds3,4and7~10greatly improve thedegradation efficiency of azo dye as a heterogeneous catalyst, demonstrating the potential applicationas catalytic materials.