含硫稀土簇合物的设计、合成及性能表征

The strong anisotropy and large spin-orbit coupling of lanthanide make itself fascinating candidates for the synthesis and design of molecule based magnetic materials. However, owing to the shielding effect of the inner electrons to the outer electrons in lanthanide ions, the magnetic exchange coupling among lanthanide ions are very weak, and hard to be modulated. Sulfur-containing Schiff base ligand can enhance the magnetic interaction through the bridging soft donor S atoms in lanthanide clusters, and hence, promote the synthesis, design and modulation of the properties of lanthanide single molecular magnets. In this project, serials of Schiff base ligands were synthesized by using sulfur-containing amino acid, mercaptan derivatives, Thiourea derivatives and o-vanillin as raw materials firstly. And then, such ligands will react with lanthanide salts to synthesize polynuclear lanthanide SMMs. The structure and magnetic properties may be regulated by changing the sulfur coordination sites, steric hindrance and subsituents in ligands. It is expected that this research can shed light on the exploring for the origin of lanthanide magnetism, the influence of donor atoms in ligands to the magnetic interaction and coordination field of lanthanide ions, and finally, the regular regulation of magnetic properties of lanthanide SMMs.

稀土离子强的各项异性和大的旋轨耦合为设计与合成分子基磁性材料提供了一条新的可行性途径。但稀土离子间由于外层电子对内层电子的屏蔽作用导致稀土离子间磁相互作用非常弱，从而很难对其进行调控。含硫基席夫碱配体的设计合成可以为多核稀土配合物提供可能的磁性交换桥梁，从而强化稀土离子间的磁相互作用进而实现稀土单分子磁体性能的调控。在本项目中，我们预通过含硫手性氨基酸，硫醇衍生物，硫脲与邻香草醛等形成含硫的席夫碱多齿配体来设计合成稀土单分子磁体。通过改变席夫碱配体中取代基的位置，含硫配位点及位阻来调控配合物的结构，实现硫与稀土离子的桥联配位。通过对配合物磁性与结构之间的详细分析与比较，探讨材料磁性的起源，配体对稀土离子间磁相互的影响，研究配合物结构、磁相互作用对磁性的调控作用，为实现分子基稀土磁性材料的设计及功能调控提供借鉴。

本项目基于设计合成多齿含硫席夫碱配体，利用多齿配体的螯合作用促进软碱硫原子与稀土离子的配位，拟得到S原子配位及桥联的稀土配位簇合物，考查配体场、稀土离子通过S原子传递磁相互作用对单分子磁体性能的影响。研究中，探索合成了三个系列（苯硫酚、氨基硫脲、半胱胺）为硫源的席夫碱配体，并与稀土离子（3d/4f）进行了配位，获得了7个系列的稀土配合物（簇合物），摸索了配合物的合成条件、荧光、离子识别、磁性等性能。这些研究结果对具有特定结构的稀土含硫配合物（簇合物）合成、结构及荧光、磁性等方面提供了借鉴，为后续进一步开展稀土单分子设计、合成及应用提供了一些有益的思考和认识。