Structural Manipulation And Properties Of Carboxylate-based Coordination Polymers

The design and assembly of various coordination polymers are currently of great interest due to the richness of their implications in fluorescence,electricity, magnetism and so on.Coordination polymers were mainly assembled with coordination bonds,and some molecular interactions or host-guest interactions as well. The corresponding bond energies are relatively low,compared to the covalent bonds, which makes the assembly of coordination architectures easily affected by external physical or chemical stimuli.Thus,one could obtain different architectures at ease by carrying out a reaction in different solvents,or under different pH value or different temperature,and so on.In this research field,to fully understand the intrinsic assembly of coordination polymers is still one of the most attractive fields.Herein,the subject of this dissertation is investigation of the influence of factors on assembly of carboxylate-based coordination polymers.Firstly,two 2D coordination polymers,a 2D three-fold interpenetration network of 1 and a 2D bilayer framework of 2,were synthesized at different pH condition based on copper(ⅡI) and trimesic acid.At higher pH conditions,the pH effect on the structure of the complex is not realized by influencing the deprotonation of the organic acid,but rather by introducing hydroxyl groups;the introduction of hydroxyl groups favors the formation of a polynuclear copper(Ⅱ) coordination polymer. Furthermore,In the Mn(Ⅱ)/FDC system,a 1D chain of 3 and a 3D open framework of 4 were synthesized by tuning the solvent system.Through investigation on their structural differences,the coordination environment of metal ions is controlled by the coordination ability of the solvent molecules,giving control over the structures of the coordination polymers.Secondly,the aim of this part is construction of novel coordination polymers based on THFTC and Cu(Ⅱ).By change of the alkaline metal ions,four novel alkaline metal ions-participated coordination polymers 5-8 have been prepared.Structural analysis shows that the radiuses of alkaline metal ions play a key role in the assembly process. When the alkaline metal ions were not introduced into the THFTC/Cu(Ⅱ) system, compound 9-11 were obtained.According to the magnetic measurements,compound 9 exhibits antiferromagnetic property,whereas,ferromagnetic behavior is observed in compound 10.Thirdly,based on the research of part two,2,2'-bipy and 4,4′-bipy were introduced into the THFTC/Cu(Ⅱ) system,respectively.On the one hand,by the introduction of 2, 2′-bipy as auxiliary end ligand to the metal centers,three compounds 12-14 ranged from 0D to 2D structures were obtained under microwave radiation and solvothermal condition.The magnetic study of compound 14 reveals ferromagnetic interactions between the copper centers in the compound.On the other hand,when 4,4′-bipy was introduced as a auxiliary pillar-like ligand,two novel open frameworks of 15 and 16 were prepared.