Synthesis, Structural Characterization And Properties Of Coordination-driven Supramolecular Complexes Based On1,3,4-Oxadiazole And Fluorene-based Ligands

Metal-organic frameworks represent a new class of hybrid organic-inorganic supramolecular materials comprised of ordered networks formed from organic electron donor linkers and metal cations. They exhibit extremely high surface areas, as well as tunable pore size and functionality, so they have enjoyed extensive exploration, including gas separation, catalysis, drug delivery, optical and electronic applications, and sensing. In order to obtain functional MOFs with novel structures, a series of imidazole-terminated and benzimidazole-terminated organic ligands were designed and synthesized. And their self-assembly chemistry were studied,19new compounds were prepared and characterized by single-crystal X-ray diffraction and powder X-ray diffraction, infrared spectroscopy, elemental analysis. The luminescent properties and anion exchange properties of some compounds were investigated.I Because fluorene is easy to be modified and has good optical properties, twelve imidazole-terminated and benzimidazole-temiinated symmetric organic ligands which are based on fluorene were synthesized and characterized by1H NMR, IR, melting point, fluorescence and elemental analysis.Ⅱ Five novel compounds were obtained with the presence of organic ligand2,7-bis (1H-imidazol-1-yl)-9,9’-dimethyl-9H-fluorene and cobalt nitrate. The purity of1-5and the thermal stabilities of1-4were characterized. Furthermore, the anion exchange properties of5was studied, the result showed that NO3-can be exchanged by N3-, SCN-, ClO4-, PF6-. And5realized the anion exchange among anions with different shapes.III Twelve new novel coordination compounds were obtained based on fluorene-based ligands and transition metal salts. The luminescent properties of some compounds were investigated, and the influences of metal ions and co-ligands on the structures of MOFs were also studied.IV Based on the study of our previous research group members, six1,3,4-Oxadiazole semi-rigid organic ligands were synthesized and their self-sassembly chemistry were studied in the present of co-ligands and transition metal. Two compounds were obtained and characterized.This study demonstrated that imidazole-terminated fluorene-based organic ligands have rich coordination modes. Some of the compounds are provided with good fluorescence properties which lay the foundation of preparation for optical materials.