Research Of Metal-Organic Frameworks Based On Imidazole/Carboxylate Functionlized Ligand

The aims of this thesis are to design and synthesize the novel metal-organic frameworks and explore their properties based on the principles of supramolecular chemistry, porous materials, crystal engineering and coordination polymers. Thus new rigid organic ligands bearing imidazole/carboxylate groups were designed and used for the assemble reactions with transition metal ions. The effect of the torsion of the ligands on the crystal structures and properties of the compounds is discussed.(1) A series of rigid imidazolate/carboxylate functionalized ligands, X-(5,7-dioxopyrrolo[3,4-f]benzimidazole-6-yl)benzoic acid (X=4,4-DPBB;X=3,3-DPBB; X=2,2-DPBB) were designed, synthesized and characterized.(2) The three ligands were used for the assemble reactions with Zn2+/Cd2+/Cu2+/Co2+ions. Five compounds,[Zn(4-DPBB)(H2O)]·DMSO·0.5MeOH (1),[Cd(3-DPBB)(DMA)1.8(H2O)0.2](2),[Cu(3-DPBB)(DMSO)(DMA)](3)[Cd(2-DPBB)(DMA)2](4) and [Co(4-DPBB)(H2O)(DMSO)]3H2O (5) were synthesized and structurally characterized (where DMSO=dimethylsulfoxide, DMA=dimethyl acetylamide). Single crystal X-ray analyses show that the compounds1to4are all based on3-connected single metal nodes and3-connected spacers, while in5the ligand acts as3-connected nodes and the two independent metal ions are used as2-connected and4-connected nodes. Compounds1and2bear a2D (6,3)-net structure, while3and4have a2D (4,8)-net. Compound5bear a3D diamond structure.(3) The five compounds were further characterized by FT-IR spectra, XRD, TGA and Luminescent analysis. Compared with2,3and4,1and5exhibit relative high thermal stability and is stable up to～550℃. Luminescent analysis indicates that1and2exhibit linker-localized emissions while4has ligand-to-metal charge transfer (LMCT) emission.