Synthesis And Properties Of N-heterocyclic Ionic Liquids Containing Carboxylic Group And Their Coordinations

As a new type of designed solvent, ionic liquids (ILs) have attracted much attention and have beenwidely studied and applied in various fields. Recently, one of the important tasks is to design and synthesisthe functionalized ionic liquids, and then develope their applications. As part of the National NaturalScience Foundation of China (No.21173069), we designed and synthesized a series of N-heterocyclic ionicliquids containing COOH group (COOH-N-ILs) and determined the crystal structures and physicochemicalproperties. Also, we have studied the structure and properties of zinc, lead, and rare earth ions–organicframeworks with COOH-N-ILs under the hydrothermal method, which provides the reference to investigatethe coordinations formed by metal ion and COOH-N-ILs, and explore their potential applications. Thepresent thesis consists of the following parts:1. We successively synthesized and purified12kinds of COOH-N-ILs. These ionic liquids have beencharacterized by Infrared spectroscopy, Nuclear Magnetic Resonance, pKa determination, and thermalanalysis technology. At the same time, we obtained the single crystals of5kinds of ionic liquids, anddetermined theirs structures.2. Through the hydrothermal and solvent evaporation methods, we successfully constructed five newzinc (II) frameworks based on COOH-N-ILs. These compounds were characterized by using infraredspectroscopy, Thermogravimetry and Differential Scanning Calorimetry, X-ray diffraction and fluorescentanalysis technology. It was found that the complexes based on bipyridine ring are lower thermal stabilitythan those based on imidazole ring. This may be due to the difference in the structure of parent ring.3. Using imidazolium-based ionic liquids containing carboxylic acid as a ligand, we successfullysynthesized three Pb (II) metal-organic compounds, and determined their structures. These compoundswere furthere characterized by Infrared spectroscopy, Thermogravimetry and Differential ScanningCalorimetry, X-ray diffraction and fluorescent analysis technology. The experimental results show that thecoordination ability of imidazolium-based ionic liquid decreased significantly with the addition of thepyridine ligand.4. Selecting the synthesized [CH2COOHimCH2COOH]Br as a ligand, we designed and synthesized three kinds of rare earth metal-organic compound. These compounds were further characterized by IR,TG-DSC, X-ray diffraction, single crystal diffraction, and fluorescent spectrum technology. The resultsshow that all of them have well fluorescent properties, and can be applied in the preparation of luminescentmaterials.