| Because of their potential applications in magnetism, absorption, separation, catalysis and molecular recognition, coordination polymers with its own properties but high Tc have attracted considerable interest in synthesis materials. The relationship between the magnetic interaction and structure of rare earth coordinated with the first series transition metal at different circumvents was explored to understand the magnetic exchange mechanism, which offered reliable theory to use crystal engineering for designing and synthesizing new molecule-based magnet of RE-transition metal heteronuclear complexes and to improve the properties of RE function materials.Presently, two common approaches were employed to design and assemble coordination polymers. One was that discrete metal-organic clusters connected via O-H or N-H to produce coordination polymers. The other was that multidentate organic ligands were coordinated with metal ions to construct infinite framework. These intriguing structural-topologies such as chain, ladder, grid, brick wall, honeycomb and channel have been reported in literature. Although there are many reports about magnetic property on coordination polymers, there is little reports about magnetic property on a series of complexes comprised rare earth and the first series transition metal.Withα-methacrylate as bridged ligand and (or not) 1,10-phenanthroline as neutral ligand, twelve novel 4f-3d heteronuclear complexes of different dimensions and one Cu complex have been synthesized and characterized. The structure and magnetic property of the complexes have been measured.Chapter One. The status of coordination-polymer research related to magnetism were investigated. The purpose and significance of the selected theme were illuminated.Chapter Two. 11 RE-Cu and RE-Zn complexes without neutral ligand were synthesized and their crystal structures also have been determined by X-ray diffraction. They are in totally new structure. (1) Totally 7 RE-Cu complexes which are bridged only by carboxylate groups have been synthesized. The two-dimension supra-molecular complexes {[RECuL4(H2O)4]L}n(RE = La, Nd, Gd) have been obtained, in which freeα-methacrylatic anions were connected with coordinated water molecules in cationic chain [...Cu...RE...Cu...RE...]+. Other complexes, {[RECu2L7(H2O)-2H2O] 4}n(RE=Tb, Dy, Er, Y), were bridged by seven carboxylate groups with central ionsto form 1D polymeric chain [...RE...Cu...Cu...RE...Cu...Cu...RE...]. The difference of structural properties between the two kinds of RE-Cu complexes showed the law that Lanthanide could be divided into two parts according to the similarity of their physical and chemical properties, with Gd and Tb as the demarcation point of light rare earths and heavy rare earths. The variation of average RE-O bond length in two groups was in accordance with the linear changes of RE3+ radii.(2) Totally 4 RE-Zn complexes with isomorph have been synthesized, which were 1D Zigzag infinite chain [.. .Zn.. .RE.. .Zn.. .RE...] bridged only by carboxylate groups. The structure of the complexes was similar to that of RE-Cu heteronuclear complexes, which is propitious to study the magnetic properties of the complexes.Chapter Three. In this chapter, an unreported transition metal complex [Cu3L2(OH)2(phen)2(H2O)2](NO3)-2H2O and two RE-Co compounds [RE2Co2L10(H2O)2(phen)2]·nH2O [RE=La(n=2), Nd(n=0)] were synthesized with 1,10-phenanthlorine as neutral ligands andα-methacrylatic as anionic ligands. The Cu complex with totally new structure was center symmetric, with the intermediate position situated at of the middle of three Cu(Ⅱ) ions. The three Cu(Ⅱ) ions in the molecule are in a linear arrangement linked byα-methacrylatic and hydroxide groups with two bridge-mixed CuO2-OH/RCOO- Cu1 units. A one-dimension structure has been obtained by hydrogen bonds along the a axis through two six-ring cycle. The RE-Co compounds was a discrete tetranuclear Co- RE - RE -Co molecule, because the coordination of phen ligands with Co ions prevents the formation of an infinite net structure. The Co and RE ions are bridged by three carboxyl groups withμ-2(COO) mode, while the symmetry-related RE ions are linked by two carboxyl groups. Two-dimensional network structure along b axis of [La2Co2L10(H2O)2(phen)2]·2H2O have been obtained due to hydrogen bonding whichare linked with uncoordinated water molecules andα-methacrylate anions.Chapter Four. All of the above complexes have been characterized by temperature dependence of magnetic susceptibilities. The magnetic property of complexes such as {[RECuL4(H2O)4]L}n(RE = La, Nd), {[RECu2L7(H2O)·2H2O]4}n (RE=Tb, Dy, Er, Y), [RE2Co2L10(H2O)2(phen)2]·nH2O [RE=La(n=2), Nd(n=0)] indicate that there exist anti-ferromagnetic interaction, while ferromagnetic interaction exists in the complexes of {[GdCuL4(H2O)4]L}n, [Cu3L2(OH)2(phen)2(H2O)2](NO3)·2H2O.It is difficult to clarify what contributes most to the magnetic interaction between rare earth and transition metal ions, because the change in magnetic properties is related with many facts such as the different ions, the coordination environments and value state of the ions, et al. Moreover, the splitting of crystal field and orbital contribution also made the situation complicated for quantitative analysis. Therefore, an approach comparing the magnetic properties of the complexes was applied, which was to half - qualitatively appraise the nature of magnetic interaction between lanthanide and transitional metal ions. Strictly speaking, this approach is significantly rough, but it is easy to process the complicated systems. Using this method, it has been confirmed that paramagnetic interaction hardly presents between Cu and RE ions , or it is at least very weak. It is concluded that magnetic properties of complexes {[LaCuL4(H2O)4]L}n(RE = La, Ce, Nd, Eu, Gd) and {[RECu2L7(H2O)·2H2O]4]}n (RE = Y, Tb, Dy, Er) at room temperature exhibit basically their magnetic behavior of each metal ion though magnetic behavior is generally complicated in the heteronuclear complexes. Although the carboxylic groups have conjugate property, but they are not excellent bridges transmitting magnetic coupling interactions between RE ions and transition metal ions. Meanwhile, the results also indicated that the unpaired electron of the RE ions were affected little by the circumstance changing, because it was situated at 4f orbital which are well-shield by the occupied outer shells of 5s and 5p electrons.The research results and creative fruit were described on the end of the thesis.
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