3d-4f混金属配合物磁性质的研究

发布时间：2018-01-22 15:30

本文关键词： 单分子磁体多齿螯合配体 3d-过渡金属 3d-4f混金属磁性　出处：《武汉工程大学》2016年硕士论文　论文类型：学位论文

【摘要】：配位化学是当前无机化学的重要分支,它与有机化学、物理化学、生物化学、固体化学、材料化学和环境化学等相互渗透,已经成为众多学科的交叉点。单分子磁体(SMMs)属于配位化学中重要研究领域,相比于传统磁性材料,单分子磁体具有尺寸小、易加工、能耗低、传输效率高等特点,并在磁性信息储存和量子计算等方面存在潜在应用。由于3d过渡金属配合物在结构与磁性方面的局限性,人们对单分子磁体配合物的研究逐渐转向了3d-4f混金属配合物的研究,这归功于3d-4f混金属配合物的能垒和阻塞温度相比过渡金属单分子磁体的确有明显提高。这给人们对于单分子磁体的设计提供了新思路,也促进了人们对新的合成方法的不断探索。本论文介绍了单分子磁体的特点,综述了近年来过渡金属(3d)和稀土金属(4f)及3d-4f混金属簇合物的研究进展,并设计、合成了一系列结构新颖的配合物。本文在设计合成3d-4f过渡-稀土金属单分子磁体配合物的过程中,也合成出了一些3d过渡金属配合物,其中一些还具有较好的单分子磁体性质,为进一步合成过渡-稀土混合金属配合物打下基础。主要研究内容如下:第一章为绪论。简要介绍配位化学的研究背景、金属配合物的性质及功能、以及分子磁体简介,并着重阐述了单分子磁体的研究进展,其中包括基本合成方法和最近人们对该领域的的探索成果,最后提出本论文的研究构想。第二章尽管在反应体系中加入4f稀土金属盐,但得到的6个配合物稀土离子都没有进去,形成6个3d过渡金属配合物,并对这些配合物进行单晶结构、元素分析、红外光谱表征并对部分化合物的磁性进行了测试和详细表征。这六个配合物分别为:一个[Mn_6Na_4]二聚体配合物、一个[Fe_6O_2Cl_4(hmp)_8]·Fe_2OCl_6(其中Hhmp=2-吡啶甲醇)配合物、一个[Fe_7]配合物、一个八面体[Fe_6]配合物、一个[Ni4]配合物及一个[Mn_7]配合物。通过磁性研究发现[Mn_7]配合物具有单分子磁体所具有的频率依赖现象。第三章为了获得过渡-稀土(3d-4f)混合金属配合物,在含有2,2-二吡啶酮和2,6-吡啶二甲醇混合配体的溶液中加入3d过渡金属Fe盐和4f稀土金属盐,获得了四个3d-4f混合金属配合物[Fe_4Ln_2](Ln=Dy、Ho、Er、Gd,这四个化合物是目前第一个含有混合配体的3d-4f混金属配合物),并对所得到的四个配合物分别进行单晶结构分析、元素分析、红外光谱表征和磁性研究。由于四个化合物的结构性质相似,在本文中具体描述了其中一个化合物[Fe_4Ho_2]的结构,通过磁性研究发现[Fe_4Dy_2]配合物在2000 Oe外加场下交流磁化率虚部具有单分子磁体所拥有的频率依赖现象,并出现峰值,通过阿伦尼乌斯公式拟合,有效能垒达到22.07 K。
[Abstract]:Coordination chemistry is an important branch of inorganic chemistry, which permeates with organic chemistry, physical chemistry, biochemistry, solid chemistry, material chemistry and environmental chemistry. Monolayer magnets (SMMs) are important research fields in coordination chemistry. Compared with traditional magnetic materials, monolayer magnets have small size, easy processing and low energy consumption. High transport efficiency and potential applications in magnetic information storage and quantum computation. Due to the structural and magnetic limitations of 3D transition metal complexes. The study of monolayer magnets has gradually turned to the study of 3d-4f mixed metal complexes. This is due to the fact that the energy barrier and blocking temperature of the 3d-4f mixed metal complexes are obviously higher than that of the transition metal monolayer magnets, which provides a new idea for the design of monolayer magnets. It also promotes the continuous exploration of new synthetic methods. In this paper, the characteristics of monolayer magnets are introduced. The research progress of transition metal (3d) and rare earth metal (4f) and 3d-4f mixed metal clusters in recent years are reviewed and their designs are also reviewed. A series of novel complexes have been synthesized. In the process of designing and synthesizing 3d-4f transition metal monolayer magnets, some 3D transition metal complexes have also been synthesized. Some of them also have good properties of monomolecular magnets. The main research contents are as follows: the first chapter is introduction. The background of coordination chemistry, the properties and functions of metal complexes are briefly introduced. A brief introduction of molecular magnets is given, and the research progress of monolayer magnets is emphasized, including the basic synthesis methods and the recent achievements in this field. In the second chapter, although 4f rare earth metal salts were added to the reaction system, the six complexes were not found in the reaction system, and 6 transition metal complexes were formed. These complexes were characterized by single crystal structure, elemental analysis, IR spectra and magnetic properties of some compounds. [Mn_6Na_4] dimer complex, a. [Fe_6O_2Cl_4(hmp)_8] 路Fe2OCl6 (Hhmp-2-pyridyl) complex, a. [Fe_7] complex, an octahedron. [Fe_6] complex, a. [Ni4] complex and a. [Mn_7] complexes. [Mn_7] complexes have the frequency dependence of monolayer magnets. In chapter 3, in order to obtain transition rare earth 3d-4f metal complexes, the complexes contain 2O2-dipyridinone and 2. Four 3d-4f mixed metal complexes were obtained by adding 3D transition metal Fe salt and 4f rare earth metal salt into the solution of 6-pyridine dimethanol mixed ligand. [The four compounds are the first 3d-4f mixed metal complexes containing mixed ligands. The four complexes were characterized by single crystal structure analysis, elemental analysis, infrared spectroscopy and magnetic analysis. Because the four compounds have similar structure and properties, one of them is described in this paper. [The structure of Fe_4Ho_2 was found by magnetic study. [The Fe_4Dy_2] complex exhibits the frequency dependent phenomenon of monolayer magnets in the imaginary part of AC magnetic susceptibility under the external field of 2000Oe and the peak value is obtained, which is fitted by the Arrhenius formula. The effective base reached 22.07 K.
【学位授予单位】：武汉工程大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O641.4

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