Syntheses Of Applications Of Functionalized Metal-Organic Frameworks With Nitrogen Heterocyclic Acid Ligands

In the fast growing field of porous coordination materials, metal-organic frameworks (MOFs), is of great interest to achieve systematic functionalization of the pores for the applications in gas absorption, catalysis, drug delivery, chemical sensing and so on. Compared with other traditional porous materials, such as zeolites and activated carbon compounds, crystalline microporous MOFs possess many outstanding features such as control of the functionalities in pores and unpredictably large surface areas. Modifying the ligands with organic methods will make MOFs more useful in more applications. Constructing the structures with functional groups by crystal engineering theory, MOFs can be applied in more Fields such as luminescence, electricity, magnetism, and catalysis and gas storage. Therefore, assembling MOFs with functional groups have a great significance in developing novel materials.Designing the carboxylate ligands with functional sites (such as immobilisated and uncoordinated NH and SH groups), MOFs have more opportunities to enhance the applications of adsorptions and catalysts. Herein, with the ligands of functional sites, we obtained a series of functional MOFs. The influences of the gas and dye adsorptions by the functional sites have been studied. Moreover, the catalytic activities of the materials have been studied as well. All the results have been stated as follows:1. Firstly, we synthetized a new dicarboxylic ligand (H2DDQ) with free chelating amino sites. With this ligand, we successfully construct MOFs with free functional sites (Cu-DDQ、Zn-DDQ and Pb-DDQ). The porosities of Cu-DDQ, Zn-DDQ and Pb-DDQ are 33.5,34.7 and 23.1% respectively. Gas adsorptions indicated the lower N2 adsorptions and higher CO2 adsorptions. Especially to Cu-DDQ, it can absorb CO2 of 180cm-3 g-1 at 273 K and 800 torr. Dye adsorption experiments show that Zn-DDQ and Cu-DDQ can separate the dye mixture quickly. As a heterogeneous catalyst, Cu-DDQ can catalyze aldehydes well in the cyanosilylation reactions.2. We synthetized two isostructural Ln-MOFs (Er-DDQ and Eu-DDQ) with H2DDQ. The porosity of Er-DDQ is 18.7%. The lower N2 and CO2 adsorptions are due to the smaller pores. Because of the existence of free chelating NH groups, Er-DDQ can absorb more RhB. As a heterogeneous catalyst, Er-DDQ can catalyze aldehydes well in the cyanosilylation reactions.3. Adjusting the reaction temperature and pH, three isostructural Ln-MOFs were obtained with larger pores (Y-DDQ、Dy-DDQ and Eu-DDQ). The porosity of Y-DDQ is 40.7 and the 3D structure shows a sra net. The BET surface area and pore size of Y-DDQ were calculated from the N2 and Ar adsorptions. Due the existence of free chelating NH groups, CO2 adsorptions are larger than most of what reported. Y-DDQ show good adsorptions of cationic dyes and good catalytic activities of cyanosilylation reactions.4. A porous metal-organic framework (Zn-BDC), was synthesized hydrothermally with the decomposition of 2,3-di(1,2,4-triazole) quinoxaline ligand. Considering the certain size of the cages, Zn-BDC can separate organic compounds with different sizes through a MOF-column chromatographic method and deliver 5-fluorouracil which can act as an anticancer drug. Zn-BDC has also been employed as a support for Pd Nanoparticles. The results of catalytic hydrogenation of 4-nitrophenol (k=0.014 s-1) demonstrate that the catalytic activity of Pd@Zn-BDC is superior enough compared to most Pd catalysts reported.5. Two lanthanide coordination polymers (La-TTTA) and Nd-TTTA) have been hydrothermally synthesized through the reaction of lanthanide ions with the flexible tripodal ligand (H3TTTA). La-TTTA show good recognition of amine molecules and cations. La-TTTA acts as efficient Lewis acid catalysts for the cyanosilylation of benzaldehyde...