Syntheses And Properties Study Of Alkaline Earth Metal-organic Frameworks Based On N-containing Carboxylates Ligand

During the past decade, the synthesis and investigation of highly organized metal-organic frameworks (MOFs) have attracted a lot of interest in supramolecular chemistry and materials science due to their potential applications in diverse areas such as molecular selection, gas storage, anion exchange, catalysis and so on. So far, the most recognized method of designing structural architecture is using metal ions with useful organic ligands directly, among kinds of organic ligands used as linkers in the design of supramolecular networks, aromatic polycarboxylates (O-donor) and N-containing heterocyclic rings are the most widely used due to their structural rigidity and flexible coordination modes. In recent years, some heterocyclic carboxylic acids have also been employed to prepare metal coordination polymers with fascinating architectures because the heteroatoms in these acids may serve as potential coordinating sites, which can yield the formation of the structures of higher dimensions even the special structure of interpenetration and spiral. In addition, the weaker noncovalent interactions, including hydrogen bonds orπ···πinteractions are also play an important role in the self-assembly process. However, more subtle conditions, such as pH values, molar ratio of reactants, counteranions and solvent etc., can effect the final structures. Hence, there is still a long way to predict the discrete coordination polymers through the self-assembly in crystal engineering before it will be possible to say that these ambitious projects have been fully realized.With a growing interest in the area of coordination polymers and host/guest chemistry, a certain number of Group II coordination architectures have been reported in the literature. The oxidation states and atomic radii of alkaline earth metals are comparable to divalent transition metals and rare earth metals, which could, in principle, lead to similar networks in the solid states. The main contents of the thesis are as following:1. we use 3-pa and 4-pa (3-pa = pyridine-3-carboxylate, 4-pa = pyridine-4-carboxylate) as the organic ligand and alkaline earth metal as central ions, which were placed in the Teflon-lined stainless steel autoclave, and the autoclave was sealed, heated for several days. The rresults show that reacted condition and temperature have influence on the final structure.2. we use AmTAZAc as the organic ligand and alkaline earth metal as central ions under the layer method to explore the effect of different ligand on the final structure.3. In contrast with the alkaline earth metal ions, the reactions of transition metal ions and organic ligands were used to show that different metal ions have influence on the final structure.