Construction And Properties Of Coordination Polymers Based On Multicarboxylate Ligands

In this thesis,series of coordination polymers were successfully obtained based on multicarboxylate ligands and various metallic precursors.Furthermore,their crystal structures,magnetic behaviour and gas adsorption properties were studied.The main results as follows:1.By utilizing five kinds of multicarboxylate ligands and salicylaldoxime {Mn₆}precursor,coordination polymers exhibiting 1D chain and 2D layer crystal structure were obtained.Among them,compounds 1-3 are rare cases that simultaneously exhibit single molecule magnet behaviour and gas adsorption performance.Furthermore,the direct current magnetic susceptibility of compounds 1-3 were similar to isolated salicylaldoxime {Mn₆} precursor,both of them exhibited whole antiferromagnetic interaction of {Mn₆} cluster.However,compared with isolated {Mn₆} precursor,alternating current magnetic susceptibility of compounds 1-3 were changed.Usually,for isolated {Mn₆} precursors,obvious peaks were observed in the out-of-phase of ac magnetic susceptibility.But in compounds 1-3,peaks were only observed under 2000 Oe applied magnetic field.As for compounds 4 and 5,the direct current magnetic susceptibility revealed a whole ferromagnetic interaction existed in {Mn₆} cluster,which is different from the {Mn₆} precursor.The discrepancy was ascribed to the different Mn-N-O-Mn torsion angle in those compounds.2.By using multicarboxylate ligand as linker and macrocylic nickel（Ⅱ）complex as node,fourteen coordination polymers were obtained,and their crystal structures and properties were systematic studied.The results show that the modification of macrocyclic ligand has significant effect on crystal structure,stability and gas adsorption property.In detail,the interpenetration number and pore size can be tuned.The stability of 3D porous coordination polymer can be enhanced due to the increase of C-H···π interaction.By modifying the macrocyclic ligand,the relative slip of adjacent2 D layer can be inhibited,resulting robust 2D porous coordination polymer.Furthermore,porous coordination polymers following different separation mechanism of CO2 over N2 can be gained by slighter modification of macrocyclic metallic precursor.3.By using methanetetrabenzoate ligand as linker and macrocylic nickel（Ⅱ）complex as node,an exceptional porous supramolecular network was obtained.When the porous supramolecular network was heated,it transformed into porous coordination polymer.The transformation was confirmed by single X-ray diffraction and powder X-ray diffraction.This transformation involves a change of interpenetrating dimensionality from 6-fold to 5-fold.Simultaneously,the coordination geometry of nickel（Ⅱ）is altered from square planar to octahedral geometry,corresponding to the transformation of spin state from S = 0 to S = 1.