双稳态磁性材料的设计合成以及性质研究

DESIGNED SYNTHESIS AND PROPERTIES OF BISTABLE MAGNETIC MATERIALS

王一搠

11649075

硕士

化学

张元竹

2018

2018.7.2

哈尔滨工业大学

深圳

近些年来，随着磁学理论知识的发展、磁性材料研究的深入，在分子水平上研究带有特殊磁性功能 的 材料成为了一个新兴起的学科领域。其中，具有双稳态特性的磁性材料因在光开关、热开关以及新型信息储存等电子器件材料的潜在应用而成为分子基磁性材料研究的一项热点。目前，科学家们主要集中精力在低温区存在慢磁弛豫行为的分子纳米磁体以及在室温附近具有自旋翻转特性的配合物两个方向。尽管近些年双稳态分子材料的研究取得了长足的进展， 该领域 的研究依然需要解决许多问题：如何逐个排除影响自旋翻转的内外因素，实现得到可控转变，尤其是合成在室温下发生自旋翻转或是具有较宽热滞回曲线的配合物；如何通过配体设计或者引入第二金属中心来改变整个配合物的几何构型，进一步调控配合物的晶体配位 场 以期望获得慢弛豫的分子纳米磁体 。 目前已报道的工作中很多集中在通过改变溶剂分子和抗衡阴离子来调控金属中心 间的 作用，期望以此来提高协同作用，目的是得到性质优秀的自旋翻转配合物。此外，用一些桥连配体连接单核的自旋翻转活性中心，合成双核 /多核的簇合物，可以有效提高自旋翻转中心的相互作用，对其双稳态行为产生积极的影响。基于以上的研究背景调研和思考，本论文意在采用选定的配体，用不同的合成手段，设计合成具有特定构型和磁学性能的单分子磁体和自旋翻转配合物，了解它们的磁构关系，并进行进一步性能调控：第一章，绪论，介绍双稳态分子基磁性材料的基本概念和及其研究的意义。分别介绍了分子纳米磁体以及自旋翻转化合物的相关理论知识和研究进展。重点介绍了自旋翻转化合物的基本概念，影响自旋翻转现象的因素和最近与自旋翻转化合物相关的研究热点。之后简单介绍此论文的主要研究内容。第二章，采用多种合成方法，如溶剂热、液相扩散等方法，基于 tpa (tris(2-pyridylmethyl)amine) 这一配体，设计合成了一系列平面四边形的异核双金属簇合物： ：{[Fe(tpa)][Ni(CN)4]}2·8H2O (1)、 {[Fe(tpa)][Pd(CN)4]}2·4H2O (2)、 {[Fe(tpa)][Pt (CN)4]}2·2H2O (3) 和 {[Fe(tpa)][Pt(CN)4]}2·2MeCN (4)。并对这些配合物的单晶结构进行了表征。该工作试图研究在同样的平面四方构型 Fe2M2 (M = Ni, Pd, Pt)中，不同抗磁金属中心，不同的溶剂分子，对 FeII中心的自旋翻转温度和化合物热滞回线的影响。第三章，通过溶剂挥发、气相扩散等方法，基于 enbzp ([N,N-bis(pyridine-2-yl) benzylidene]ethane-1,2-diamine)) 配体和第二辅助配体如 (4,4’-bypyridine azide) 合成了一系列 CoII配合物 ：：[Co(enbzp)(4,4’-bpy)]·(ClO4)2(CH3OH)(H2O) (5)、[Co(enbzp) (N3)2] (6)、 [Co(enbzp)(MeCN)]·(ClO4)2(MeCN) (7)和 [Co(enbzp)-(ClO4)2]2·Et2O (8)，并对这些配合物的单晶结构进行了表征。本章研究了不同的辅助配体，溶剂分子对所得的化合物的晶体结构产生的影响，并将进一步研究化合物晶体结构和其磁学性质的关系。第四章，设计合成出了两例多齿含氮配体Fe配合物 ：：[Fe(tpa)Ni(CN)4]4 ·(H2O)4 (MeOH) (9) 和 [Fe2(enbzp)(N3)4] (10)，对其结构进行分析，并对将来工作进行了展望。

In recent years, with the development of theoretical knowledge in magnetics, the study of molecular materials with specific magnetic properties has become a newly emerging discipline. Among them, magnetic materials with bistable characteristics have become a hot topic in the research of molecular–based magnetic materials due to the potential applications of electronic device materials such as optical switches, thermal switches and novel information storage. At present, scientists mainly focus on molecular magnets with slow-relaxation behavior in low-temperature regions and complexes with spin-crossover characteristics near room temperature. Although the research on bistable molecular materials has made great progress in recent years, the research in this area still needs to solve many problems: how to eliminate the internal and external factors that affect spin crossover one by one and achieve a controllable transformation, especially at room temperature. Spin crossover or complexes with broader thermal hysteresis curves occur; how to adjust and influence the ligand field by different doping metals and different ligands in order to change the geometric configuration of the complex, to obtain slow-relaxed molecular nanometers magnet. Many of the work reported so far have focused on controlling intermolecular interactions between metal ion centers by changing the solvent molecules and counter anions. It is expected that the synergistic action will be enhanced in order to obtain excellent spin-inversion complexes. In addition, the use of some bridging ligands to link the mononuclear spin flipping active centers and synthesizing binuclear/multinuclear clusters can effectively increase the interaction of the spin flipping centers and have a positive effect on their bistable behavior. Based on the above research considerations, this paper intends to design and synthesize single-molecule magnets and spin-inversion complexes with special configurations by using selected ligands, and understand the structure-property relationships of the resulting compounds.In Chapter 1, the author introduced the basic concepts of bistable molecular-based magnetic materials and the significance of the research. The related theoretical knowledge and research progress of molecular nano-magnets and spin crossover compounds were introduced. The basic concepts of spin crossover compounds, the factors affecting the spin crossover phenomenon, and the current research hotspots of spin crossover complexes were highlighted. Finally, the content of this paper was briefly introduced.In Chapter 2, a series of planar tetragonal heteronuclear bimetallic clusters were designed and synthesized based on the tpa (tris(2–pyridylmethyl)amine) ligands using a variety of synthetic methods, such as solvothermal method and liquid diffusion, namely {[Fe(tpa)][Ni(CN)4]}2·8H2O (1), {[Fe(tpa)][Pd(CN)4]}2·4H2O (2), {[Fe(tpa)][Pt(CN) 4]}2·2H2O (3) and {[Fe(tpa)][Pt(CN)4]}2·2MeCN (4). The single crystal structures of these complexes were characterized. This work attempts to investigate the effect of different doping metal centers and different solvent molecules on the spin crossover temperature and the thermal hysteresis loop of the FeII center in the same planar tetragonal configuration Fe2M2 (M = Ni, Pd, Pt).In Chapter 3, based on enbzp ([N,N-bis(pyridine-2-yl)benzylidene]ethane-1,2-diamine)) ligands and secondary ancillary ligands such as (4,4'-Bipyridine, azide), a series of CoII complexes were synthesized, namely [Co(enbzp)(4,4'-bpy)]·(ClO4)2(CH3OH)(H2O) (5), [Co(enbzp)(N3)2] (6), [Co(enbzp) (MeCN)]·(ClO4)2(MeCN) (7) and [Co(enbzp)(ClO4)2]2·Et2O (8). The single crystal structure of these complexes has been characterized . This chapter studied the effect of different auxiliary ligands and solvent molecules on the crystal structure of the resulting compound and will further investigate the relationship between the crystal structure of the compound and its magnetic properties.In Chapter 4, two polydentate nitrogen ligands Fe complexes were designed, synthesized and structurally characterized, namely, [Fe(tpa)Ni(CN)4]4(H2O)4(MeOH) (9) and [Fe2(enbzp)(N3)4] (10).

双稳态材料 单分子磁体 自旋翻转 磁性调控

bistable materials single-molecule magnets spin crossover magnetic regulation

中文

联合培养

南方科技大学

王一搠. 双稳态磁性材料的设计合成以及性质研究[D]. 深圳. 哈尔滨工业大学,2018.