高维结构中的低维分子磁性研究

Recently, lanthanide molecular materials have developed rapidly due to their unique magnetic properties. In this project, we focus on adjusting and controlling the magnetic properties of lanthanide molecular materials. New lanthanide molecular materials with different dimensionality and/or symmetry of coordination environment of lanthanide ion will be synthesized; furthermore, chemical modification to the magnetic properties of the lanthanide molecular materials will be performed to study the factors that influence the magnetic properties of the materials. Main contents of the project include: (1) to synthesize lanthanide molecular materials with different dimensionality and/or coordination environment of lanthanide ion, and to tune the dimensionality and the symmetry of coordination environment via different experimental conditions; (2) to synthesize high dimensional diamagnetic molecular materials with particular symmetry of coordination environment, which can be controlled by doping lanthanide ions with strong single-ion anisotropy, and single-ion magnet behavior of the targeted product will be investigated; (3) to modification the slow relaxation of the magnetization of the product by changing the symmetry of coordination environment of lanthanide ion using different chemical methods, such as removing terminal small molecules by increasing temperature, changing the types of coordination donor atom; (4) to study the influence of the magnetic properties systematically before and after the modification of the lanthanide molecular materials. In this way, new lanthanide molecular materials with good performance in magnetism such as magnetic response, large energy barrier and high blocking temperature could be obtained. The study of the lanthanide molecular materials in this project is valuable not only due to their contribution to the development of molecule-based materials, but also to their potential applications as multifunctional lanthanide molecular materials. This project will contribute to the corresponding research field significantly.

稀土分子材料由于其独特的磁性质而成为国际上发展最快速的前沿研究领域之一。本项目以调控稀土分子材料的磁性为目标，拟合成具有不同空间维度和不同配位环境对称性的稀土分子材料，通过化学方法调控其磁性质。主要研究内容包括：(1)制备具有不同维度的稀土分子材料，变换实验条件以调控对产物的结构维度和配位环境；(2)制备具有特定配位环境对称性的高维抗磁分子材料，通过参杂强磁各向异性的稀土离子实现对产物配位环境对称性的控制，研究其单离子磁体性质；(3)通过化学方法改变(1)和(2)中稀土离子配位环境的对称性（如升温去除端基小分子、变换配位原子的种类等）来调控产物的慢磁弛豫行为；(4)系统研究产物磁性质的变化规律，进而找到具有特殊磁功能如选择性磁响应、高能量壁垒和高磁阻塞温度等的稀土分子磁性材料。本项目不仅有助于分子材料研究的发展，而且有望得到新型多功能稀土分子材料，及时开展相关研究具有重要科学意义。

稀土分子材料由于其独特的磁性质而成为国际上发展最快速的前沿研究领域之一。本项目以调控稀土分子材料的磁性为目标，合成具有不同空间维度和不同配位环境对称性的稀土分子材料，通过化学方法调控其磁性质。围绕以上研究目标，课题组按计划开展了具有特定配位构型稀土配合物的合成与磁性质研究的工作，通过多种化学方法调控了产物的配位环境、空间维度和磁性质，主要研究成果包括：1）合成并系统地研究了同时具有高的有效能垒和大的磁滞回线的一维稀土配位聚合物，提出了稀土离子间的磁相互作用对于保持零场磁矩和增大磁滞回线的重要作用；2）系统地研究了在二维稀土配位聚合物中影响磁弛豫过程的因素，通过抗磁稀释和外加静态磁场影响磁滞现象；3）合成了金属-有机框架-磁性纳米颗粒的复合物，研究了金属-有机框架结构中磁性纳米颗粒对产物磁性质尤其是长程磁有序的影响。本项目的研究结果不仅有助于稀土分子磁性材料研究的发展，而且有望用于多功能稀土分子材料，具有重要的科学意义。