Synthesis, Structures And Properties Of Metal Organic Frameworks Based On Crown Ether Ligands

Metal-Organic Frameworks (MOFs) which formed by organic ligands and metal ions or metal clusters is one of the most active research topics in the field of solid materials. Due to highly ordered structures, easily introduction of functional groups, Metal-Organic Frameworks has a very wide range of potential applications, such as gas storage and separation, proton conductors, catalysis, optical materials, magnetism, molecular recognition, drug delivery, corrosion resistant materials and so on.The first part of this thesis studied the crown ether ligands to build MOFs. Two flexible crown ether ligands 5,5’-dibenzoic acid dibenzo-26-crown-8 (H2L/L1) and 5,5’-dipyridine dibenzo-26-crown-8 (L2) with carboxylic acid group and pyridine group respectively has been designed and synthesized. Coordination polymer {[(CH3)2NCOO]2Zn(L)(H2O)2}·xguest(Crown-1) with one dimensional chain structure was then synthesized by ligand H2L and zinc ion under solvothermal condition. We investigated the host-guest interaction of Crown-1 with six different dye molecules in acetone solution. Because Crown-1 possessed of the rich electronic crown ether rings, this coordination polymer could selectively combine with methylene blue (MB) which had matched size and charge. In addition, we obtained the crystal of H2L under solvothermal condition which provided a feasible method to obtain single crystal for some compounds with poor solubility in the low boiling point solvent.In order to gain high dimension MOFs, tetradentate ligands 4,4’,6,6’-teraethynylbenzoic acid dibenzo-26-crown-8 (L3) and 5,5’-diisophthalic acid dibenzo-26-crown-8 (L4) has been designed and synthesized and we also tried to use auxiliary ligands to connect Crown-1 which had one dimensional chain structure, such as oxalic acid, terephthalic acid, biphenyldicarboxylic acid, 4,4’-stilbenedicarboxylic acid and so on.The second part of this thesis studied hydro(solvo)thermal in-situ reactions to construct MOFs. Ligand 4,4’-bis (3,3’-dicyano)pyridine (pydcy) was easily synthesized through two simple reactions, solvothermal in-situ reactions of pydcy with Cd(NO3)2-4H2O under the similar reaction condition of different solvent media resulted in two new coordination compounds [Cd(Hpydca)(bipy)(H2O)(NO3-)]xguest (pdy-1) and [Cd(pydca)]xguest (pdy-2) [H2pydca=4,4’-bis(3,3’-dicarboxylic acid)pyridine; bipy=4,4’-bipyridine]. Due to the πtz-5s ligand-to-metal charge transfer transition, complex pdy-1 exhibited a strong emission band at 468 nm. Complex pdy-2 possessed of a 3D framework with rhombus channel of size 19.2×14.3 A and its porosity reached 56%, so we explored its adsorption performance. In addition, we obtained the structure of 4’-bis(3,3’-diamide)pyridine (pydam). It can be proved that the cyano groups of pydcy in a certain solvothermal conditions could generate amide groups, although there was no corresponding complexes.