Synthesis,Structure And Properties Of Coordination Polymers Based On N-donor Multi-carboxylate Ligands

Coordination polymers(CPs)are a new kind of crystalline materials.Due to their potential applications in magnetism,fluorescence,gas adsorption and separation,catalysis and molecular recognition and so on,the rational design and synthesis of CPs has attracted considerable attention in coordination chemistry,crystal engineering and supramolecular chemistry during the past decades.The metal-organic frameworks(MOFs),a new type of CPs,with regular cavities,high capacity for gas storage and separation and heterogeneous catalysis have attracted great interests of many chemists.Among the applications of MOFs,hydrogen bonding catalysts are widely researched in Friedel-Crafts alkylation reactions.For example,it shows good catalytic performance in the reactions of N-methylindole with trans-2-nitrostyrene,N-methylpyrrole with trans-2-nitrostyrene,and pyrrole with trans-2-nitrostyrene.In this thesis,two new N-donor carboxylate ligands were designed and synthesized successfully,namely L1 and L2.And then L1 and L2 were mixed with transition metal ions separately under solvothermal conditions to produce five CPs.Subsequently the structures and properties of these CPs were characterized.The main works are summarized as the following two aspects.(1)L1 which contains two carboxylates groups was designed and synthesized.Subsequently,the solvothermal reaction of LI and Zn(NO3)2·6H2O in different solvents afforded two kinds of metal-organic frameworks,namely compound 1 and 2 separately.The X-ray single crystal structure of 1 revealed that it was a framework constructed by Zn4O secondary building units and LI linkers,forming a 2-fold interpenetrated structure.The structure of 2 was a 3-fold interpenetrated form.The structures of 1 and 2 can be simplified as a 6-connected pcu topology.Then the performance of 2 as a hydrogen bonding catalyst was studied.Three different reactants were employed in the reactions,and the results showed that 2 can effectively catalyze the Friedel-Crafts reactions in acetonitrile.The crystallinity of 2 was maintained after three catalytic cycles.(2)Furthermore,a new semi-rigid tetra-carboxylate ligands(L2)was synthesized,and then three different CPs were obtained via self-assembly between L2 and Cu(II),Cd(II),Ni(?),namely[Cu2L(H20)3]·4.5H2O(3),[Cd2L(H20)3]·DMF·3H2O(4),[Ni2L(H2O)5]·5H2O(5).The three compounds were characterized by single-crystal X-ray diffraction,powder X-ray diffraction(PXRD),elemental analysis(EA)and thermal gravimetric analysis(TGA).3 is a two-dimensional(2-D)grid-like double-layers with a(3,5)-connected topology network.And the staggered arrangement of the 2-D layers affords a dense structure through H-bonds.Magnetic measurements revealed antiferromagnetic interactions in 3.4 was a three-dimensional CPs with a(3,3,6)-connected topology network,and 5 forms a chain-like CPs.