Hydrothermal Syntheses, Structures And Properties Of Metal-Organic Coordination Polymers Constructed From Polycarboxylic Acid And N-Containing Heterocyclic Ligands

In the past decade, metal-organic coordination polymers(metal-organic frameworks, MOFs) as functional materials have attracted considerable attention in academia and industry. It is for not only their intriguing topologies and a higher surface area compared with ?classical‘ porous materials such as molecular sieve, but also easy to be modified and designed with flexible tailor and multiple functions. It has an attractive prospect in the gas-storage, select adsorption and separation, fluorescence, electromagnetism, chiral separation and catalysis field.Based on the principle of molecular engineering, we focused our research on the synthesis conditions, reaction influencing factors(temperature, solvent, p H value, and et al.), structures and functional properties. The aims are to explore the diversified structures of metal organic coordination polymers and to examine the regulation of different organic ligands and different metal centers with the different coordination modes on the structures. In summary, in this thesis, the lanthanide ions and the transition metal ions were selected as templates, and polycarboxylic acids were chosen as linkers/counter ions to construct metal-organic coordination polymers with novel and fascinating crystal structures. These complexes were characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction. The thermal properties of some complexes and the properties of the part of the complexes were investigated.The main results are as follows:1. Two mixed-ligand coordination polymers(CPs) based on a biphenyl-based dicarboxylate ligand and 4,4’-bipyridine or imidazole co-ligand, namely, [Co(DMBDA)(bpy)]n(1)(H2DMBDA = 2,2’-di-methylbiphenyl-4,4’-dicarboxylic acid, bpy = 4,4’-bipyridine) and [Zn(DMBDA)(Im)]n(2)(Im = imidazole), were obtained under hydrothermal conditions. Compound 1 exhibits a new(4,6)-connected network with a {44·610·8}{4·4·62} Schl?fli symbol, whereas compound 2 shows a 4-connected Nb O-type topology. These coordination polymers represent two rare examples of CPs based on 2,2’-dimethylbiphenyl-4,4’-dicarboxylic acid. The solid-state luminescent behaviors of the novel CPs were also investigated at room temperature.2. Reactions of Zn(II) salt, 5-(4-(1H-imidazol-1-yl)phenyl)-1H-tetrazolate(HIPT) and 2-propyl-1H-imidazole-4,5-dicarboxylic acid(H3Pr IDC), result in a mixed-ligand coordination polymers(CPs), [Zn2(IPT)(Pr IDC)(H2O)]n(H3Pr IDC = 2-propyl-1Himidazole-4,5-dicarboxylic acid, 3) by hydrothermal method. Compound 3 displays a 3-D framework with new 3-connected topology with Schl?fli symbol of(4·8·10)(8·122), in which the 1-D Zn-carboxylate chains were bridged by 3-connected IPTligands. The thermal stabilities and luminescence properties of complex 3 have also been studied. The compound exhibits intense solid-state fluorescent emissions at room temperature.3. Reactions of Zn(II) salt, 5-(4-(1H-imidazol-1-yl)phenyl)-1H-tetrazolate(HIPT) and 2-mercaptobenzoic acid, result in a mixed-ligand coordination polymers(CPs), [Zn2(IPT)(DSDB)(OH)]n(H2DSDB = 2,2′-disulfanediyldibenzoic acid, 4) by an in-situ method. Compound 4 possesses a 2-D structure built by 1-D [Zn(IPT)]n chains and DSDB2- connectors, in which the DSDB2- is generated via in situ reaction from 2-mercaptobenzoic acid. It displays a new intricate 4-nodal {3·4·6·7·8·9} {3·6·7·8·9·10}{3·8·9}{4·6·8} topology. The thermal stabilities and luminescence properties of complex 4 have also been studied. The compound exhibits intense solid-state fluorescent emissions at room temperature.4. Two new lanthanide coordination polymers, [Er2·(5-HIPA)4·(2,2’-bipy)2]·3H2O(5) and [Sm·(5-HIPA)3·(4,4’-bipy)3·(H2O)2]·3H2O(6), have been yielded by hydrothermal synthesis. The coordination polymers crystallize in triclinic space group P-1. Complex 5 exhibits a 2D coordination network containing parallelepiped-shaped voids that occupied by the guest 2,2’-bipy molecules. Complex 6 possesses a 1D linear chain structure, and the 1D chains are linked by various 4,4’-bipy molecules to form a complicated 3D supermolecular framework. Their thermal stabilities and luminescence properties were also investigated. Both complexes exhibit intense solid-state fluorescent emissions at room temperature.5. A series of metal-organic coordination polymers have been used for the removal of phthalic acid(H2-PA) and diethyl phthalate(DEP) from aqueous solutions via adsorption. The adsorption capacities of complex 2 and 5 were much higher than that of a commercial activated carbon. Because the surface area and pore volume of the adsorbents showed no favorable effects on the adsorption of H2-PA, the remarkable adsorption with complex 5 suggests a specific favorable interaction(electrostatic interaction) between the positively charged surface of complex 5 and the negatively charged PA anions. In addition, acid–base interactions also have a favorable contribution in the adsorption of H2-PA, based on the adsorptive performances of OH-functionalized MOFs and adsorption over complex 5 at acidic condition(p H = 3.5). The reusabilities of complexes 2 and 5 were also demonstrated after simple washing with methanol. On the other hand, complex 5 was not effective in adsorbing DEP probably because of little charge of DEP in a water solution.