Syntheses, Structures And Properties Of Coordination Polymers With 2-Nitro-Biphenyl-4, 4'-dicarboxylic Acid

In recent years, coordination polymers (metal-organic framework) are currently attracting considerable attention, owing to their potential applications in gas storage and separation, ion exchange, sensor technology, catalysis, magnetic and optical properties etc. as well as due to their intriguing architectures and topology.In this paper, aromatic dicarboxylate 2-nitrobiphenyl-4,4'-dicarboxylic acid (H2nbpdc) was used as bridging ligands between metal ions, in combination with the use of different pyridyl-containing ligand as terminal or bridging ligands to create new coordination networks. Fifteen new coordination polymers, including one dimensional, two dimensional, and three dimensional structures, have been prepared, and the thermostability and magnetic of some of the complexes have been characterized.This dissertation covers the following three parts:1. Coordination compounds with H2nbpdc:(ⅰ) The ligand H2nbpdc was prepared according to the literature method by us; (ⅱ) solvothermal reactions and evaporation at room temperature of H2nbpdc and metal ions of Co(Ⅱ), Ni(Ⅱ), Zn(Ⅱ), Mn(Ⅱ) and Cd(Ⅱ) afforded five coordination compounds. In all these compounds, compound 1 and 2 are isomophous framorks, X-ray analyses revealed the structures of the compounds 1 and 2 consist of ID zigzag chains, which are linked to a 3D net through hydrogen bonding. Magnetic analysis on the compound 1 and 2 revealed an antiferromagnetic interaction through the aqua bridge, (ⅲ) Compound 4 exhibits a 2D (4,4) layer net with the [Mn2(COO)2] cluster and carboxylate ligand. Compound 5 consists of twist ID ladder-like chains, which is generated to a 3D architecture with an 3,4-connected binodal topology based on carbon atoms of the carboxylate group as nodes.2. Coordination polymers tuned by the terminal ligand (Py):With py as coligand, four metal-organic coordination polymers have been synthesized by hydrothermal reactions with metal ions of Co(Ⅱ), Cu(Ⅱ) and Zn(Ⅱ). In compound 6, the tetranuclear clusters with mixed carboxylate and water bridges serve as 6-connected nodes and are cross-linked by dicarboxylate ligands to give a 3D framework with pcu topology. Complex 7 contains ID coordination chains hydrogen-bonded into a 3D supramolecular metal-organic architecture, alao form three cyclic motifs. The structure of complex 8 and 9 consist of a 2D layers, and the packing modes of the frameworks were analyzed based on theπ-πinteractions. The framework stability properties of some of the complexes have been characterized.3. Co(Ⅱ) and Mn(Ⅱ) coordination polymers with H2nbpdc and different bipyridyl bridge ligands:Hydrothermal reactions of H2nbpdc and Co(Ⅱ)/Mn(Ⅱ) in the presence of auxiliary ligands (4,4'-bipy, bpe, bpa) and bases afforded three 3D coordination compounds(10-15). Compound 10 contains 2D coordination layers assembled into 2-fold interpenetrated 3Dα-Po nets through O-H-O hydrogen bonding, which involves protonated carboxylic groups; 11 is a 3D metal-organic framework with 3-fold interpenetration and with a rare 4,6-connected topology{4462}{48668}. Compound 12 exhibits a 3D metal-organic framework with the [Co4(COO)4(H2O)2] cluster and has a luxuriant hydrogen bonding. With bpee as co-bridge,13 is also a 3D metal-organic framework with 3-fold interpenetration but with a different topology, In complex 14, the trinuclear [Co3(COO)6] clusters with carboxylate and bpea bridges serve as 6-connected nodes by dicarboxylate ligands and bpea auxiliary ligand to give a 3D framework with 3-fold interpenetration and with pcu topology. Compound 15 is also a 3D structure with [Mn(bipy)]n and nbpdc2-; Magnetic analysis on the compound 14 revealed a ferromagnetic interactions in carboxylate bridged [Co3(COO)6] cluster.