Assembly And Fluorescence Properties Of Metal-organic Frameworks With High-connected Organic Ligands

Coordination polymers are constructed by organic ligands and the metal ions via theconnection bond,having a complex structure of the unlimited network of highly regular.Coordination polymers possess high surface area, unsaturated metal sites, high thermalstability and other characteristics, so coordination polymers have a very good applicationprospects in nonlinear optical materials, magnetic materials, superconducting materialsand catalysis and so on.Therefore it also gain more and more concern and attention fromthe chemists. Generally, Coordination polymers with specific structure and function canbe assembled by selecting the types of metal ions and organic linkers,but to construct CPswith the high stability essential is very tough.Consequently, utilizing highly-connectedligands to construct stable architectures has been verified as an effective way to solve thisproblem.In the thesis,on one hand, utilizes two kinds of different substituent position ligandscyclotriphosphazene,hexakis(4-carboxylato-phenoxy)cyclotriphosphazene (H6L1) andhexakis(3-carboxylato-phenoxy)cyclotriphosphazene (H6L2) with Eu(NO3)3·6H2O inH2O/DMF under similar synthesis conditions produced three new compounds.Compounds1and2display a2D layer crystal structure with adistinct topological networkincorporating the extended hexa-carboxylate ligand L1; in contrast,3has a1D crystalstructure with the highly distorted hexa-carboxylate ligand L2. In these three compounds,the ligands L1and L2are fully deprotonated, whose six extended carboxyl arms connectsix same or different metallic nodes to generate metal–organic frameworks. Theluminescence properties of three compounds have been studied at room temperature inrelative detail.On the other hand, Two novel Ag(I) coordination polymers (CPs)(4and5),have been synthesized through the reaction of silver(I) nitrate and highly-connectedtetra-pyridinate ligands (TPOM1=tetrakis(4-pyridyloxymethylene)methane, TPOM2=tetrakis(3-pyridyloxymethylene)methane). Complex4exhibits the typical uninodal 3-connected four-fold interpenetrating layered hcb network, In contrast, complex5exhibits the typical uninodal4-connected four-fold interpenetrating3D dia network. Theflexible conformation and long connection arms of the different tetra-pyridiante ligandsmust be responsible for the variable interpenetrating Ag(I) coordination architectures.Additionally, results about TGA and photoluminescence spectra were also discussed.