自组装分级结构分子磁性材料及其大分子诱导的自旋交叉转换机制研究

自旋交叉（SCO）化合物由于其在室温附近独特的双稳态特性，被认为是最接近于实际应用的分子磁性材料。其中，[Fe(HB(pz)3)2]是被研究的较多的化合物之一，但其单晶容易分裂，导致其SCO曲线变缓，因而限制了其应用。针对这一问题，本项目在长期研究[Fe(HB(pz)3)2]@金属有机框架复合材料的基础之上，提出将[Fe(HB(pz)3)2]材料负载到具有微孔-介孔-大孔分级结构的MIL-101中，以获得具有高负载率、高稳定性以及多功能化的分子磁性复合材料。其中，微孔的限域作用可以提高SCO纳米单晶的稳定性并使其可以对外界分子做出响应，纳米尺度的MIL-101可以提高SCO的负载率。可预见，介孔-大孔分级结构有利于外界大分子扩散传输，从而让SCO纳米单晶更快的对外界大分子做出响应，增强其协同作用，从而改善其性能。这对于我国独立自主开发能够应用于未来量子领域的关键性材料具有重要的意义。

The spin crossover (SCO) phenomenon is the switching of a transition metal complex between two different stable ground states: the low-spin (LS) and the high-spin (HS) states. The switching between these two states may be invoked at near room temperature by different external stimuli such as molecular, light, temperature or pressure. Thus, they are considered to be the most close to the practical use of molecular magnetic materials. [Fe(HB(pz)3)2], one of most investigated SCO compounds, is less stable and single functional, which greatly limits its application. For this problem, the project propose embedding [Fe(HB(pz)3)2] into the micro-meso-macro hierarchical MIL-101 to yield molecular magnetic composites with high load rate, high stability and multi functionalization. Wherein the micro-meso-macro hierarchical structure possess faster adsorption kinetics and larger adsorption capacity, which is more advantageous to the diffusion and transmission of macromolecules and multiscale molecules. The SCO molecular could more rapidly respond to the external macromolecules, which enhance the cooperativity. Thus, the micro-meso-macro hierarchical MIL-101 could raise the SCO loading, enhance the cooperativity and improve the performance. This possesses great significance for China to develop the key materials independently which can be applied to the future quantum field.