Synthesis,Structure And Properties Of Dicarboxyl-Imidazolium Functionalized Ionic Liquids And Their Rare Coordinations

As a new type of designable solvent,ionic liquid has a wide range of research and application.The design and synthesis of functionalized ionic liquids and their applications are currently one of the hot issues in the research.In this paper,we introduced the carboxyl group into the imidazolium cation of ionic liquid,synthesized a series of functionalized ionic liquids containing two COOH groups,and determined their crystal structures,thermal stabilities and solubility in water and other physical-chemical properties.The transformation from single crystal to single crystal of partially carboxyl-functionalized ionic liquid was discussed.Finally,we selected Eu and Tb complexes containing carboxyl-functionalized ionic liquids as the object to synthesize the corresponding functional composite materials,and determined their fluorescence characteristics.This work provides the theoretical approach for the synthesis of rare earth luminescent materials.The specific work of this paper is as follows:1.1,3-Bis(carboxymethyl)imidazolium nitrate(BCINO3)ionic liquid was prepared,and its structure was determined by a sing-crystal X-ray diffraction.Its FT-IR and Raman spectra were measured and reported.The type of O-H…O hydrogen bonds were analyzed on the basis of the vibrational spectroscopy and Density Functional Theory(DFT)calculation,and coexistence of the strong hydrogen bond O-H...O and weak hydrogen bond C-H...O in the solid state was given.Additionally,the thermal stability of 1,3-bis(carboxymethyl)imidazolium nitrate and its decomposed process were proposed.2.The bis(trifluoromethylsulfonyl)imide anion(TFSI)is one of the common anions forming hydrophobic ionic liquids at room temperature.In this work,through an introduction of two carboxyl groups into the imidazolium cation,a hydrophilic 1,3-bis(carboxymethyl)imidazolium bis(trifluoromethylsulfonyl)imide(BCITFSI)organic salt was synthesized,and geometries of ion pair of anion and cation were optimized and the most stable structures were obtained.In addition,the crystal structure,vibrational spectra,physical-chemical properties such as thermal stability,pKa and solubility in water were experimentally determined.Present results are suggesting a possibility to tune the properties of ionic liquids by an appropriate change in cation structure,leading to new “designer solvents”.3.A crystal to crystal transformation process for two ionic liquids 1,3-bis(carboxymethyl)imidazolium bis(trifluoromethylsulfonyl)imide and N-(carboxymethyl)-N-methyl pyrrolidone bromine was observed,and the difference in crystal structure is attributed to the different forms hydrogen bonds,and can be indentified by FT-IR and Raman spectroscopy.Finally,differences in thermal stability were compared.4.Selecting 1,3-bis(carboxymethyl)imidazolium bromide [CH2COOHmimCH2COOH]Br as a ligand,we designed an synthesized three kinds of rare-earth-metal-complexes using hydrothermal method,and utilized the single crystal diffraction,infrared spectroscopy,thermal gravimetric analysis,X-ray diffraction and fluorescence spectroscopy to studied theirs structures and fluorescence properties.The experimental results show that this kind of rare-earth-metal-complexes have a unique structure,and show a good fluorescence performance.The fluorescent properties of the composite materials can be changed with the addition of organic additives such as 1,10-phenanthroline(phen)and 2-Thenoyltrifluoroacetone(TTA).The preparation of this kind of materials provides a theoretical approach to the exploration and application of the rare earth luminescent materials in the future.