| Magnetic materials are widely used in all aspects of our lives,such as transportation,production,medical treatment,aerospace,storage,and daily necessities.Therefore,it is very important to obtain magnetic materials with excellent performance.Since the discovery of high-temperature superconductivity,low-dimensional magnetic materials have become one of the most popular research hot topics in material chemistry and physics.Due to the emergence of quantum effects,low-dimensional magnetic materials exhibit rich and interesting magnetic phenomena,and they have been highly focused by researchers.Low-dimensional magnetic materials are synthesized by using the spin carriers and organic ligands.Spin carriers mainly include transition metal ions,actinides,lanthanides,and other metal ions.In the field of ligand selection,organic carboxylic acid ligands as multidentate bridging ligands have been widely used in the synthesis of metal-organic compounds.Carboxylic acid ligands are multidentate bridged ligands that can coordinate with metals in a variety of ways to form low-dimensional magnetic compounds with rich structures.Carboxyl complexes have unique properties and diverse coordination modes,especially their photoelectric effect,so they have broad application prospects in many fields such as nonlinear optical materials,magnetic materials,superconductor materials,and catalysis.Based on the research status of isophthalic acid and its derivatives,this thesis focuses on the design and synthesis of isophthalic acid related low-dimensional quantum magnetic materials.Using hydrothermal method and the framework of isophthalic acid and transition metal ions,two new low-dimensional quantum magnetic material compounds were successfully synthesized.Their crystal structure and purity were determined by the X-ray powder diffraction method(XRD)and X-ray single crystal diffraction methods,and the magnetic properties were characterized by the magnetic measurements and electron paramagnetic resonance(EPR).The main contents of this thesis include two parts:1.Synthesis and Magnetic Research of Cu(IPA)2(H2O)2Taking the compound Cu2(IPA)2(DMF)(H2O)with a large spin energy gap as the model and using transition metal ions and isophthalic acid as the structural framework,systematic hydrothermal synthesis was conducted in order to obtain new low-dimensional magnetic materials by changing the magnetic ion and the reactant ratio,the temperature,and p H values.The compound Cu(IPA)2(H2O)2 with a new structure was successfully synthesized.The XRD test results show that the new sample has a pure phase.Structural analysis shows that the compound Cu(IPA)2(H2O)2 has an isolated dimer structure,and the dimers form a two-dimensional layered structure through the?-?interaction.Since the distance between dimers is relatively long,the interaction between dimers is almost negligible compared with the internal interaction of dimers.The magnetic test shows that Cu(IPA)2(H2O)2 has an antiferromagnetic ground state.2.Synthesis and Magnetic Research of[Co2(CH3O-ip)(COOH)2(H2O)]nSimilar to the compound Cu(IPA)2(H2O)2,[Co2(CH3O-ip)(COOH)2(H2O)]n,with transition metal cobalt as the central ion and 5-methoxyisophthalic acid as the ligand,is also synthesized using the compound Cu2(IPA)2(DMF)(H2O)as a model and hydrothermally synthesized.The X-ray powder diffraction test results show that the synthesized sample has a pure phase.The structure analysis shows that the compound has a helical chain structure,and each helical chain is connected by a bidentate coordination method through a 5-methoxyisophthalic acid ligand.A two-dimensional layered structure is further formed in the ab plane.The magnetic measurement results shows that the ground state of[Co2(CH3O-ip)(COOH)2(H2O)]n also has an antiferromagnetic state. |
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