新型多孔/手性自旋转换材料的合成及性能研究

The study of spin transition magnetic materials has recently attracted considerable attention.These magnetic materials whose magnetic properties can be controlled by external stimuli (such as temperature, pressure,light, etc.) are expected to develop into novel molecular switching devices and molecular information storage materials.Previous research have shown that triazole-iron(II) system is quite suitable for the construction of these novel spin transition complexes.With the in-depth study of spin transition phenomenon by scientists, these multi-functional porous/chiral spin transition materials exhibit a very broad research and application prospect. Because of the combination of these functional properties(such as spin transition, porous absorption or chiral recognition properites), some new materials such as sensors,chiral materials can be obtained. The project is to build these novel multi-functional porous/chiral spin transition materials. We can use rigid aromatic or flexible alkyl hydrocarbons bridging units to connect multiple 1,2,3- or 1,2,4- triazole moieties forming poly-(triazole) ligands. Further a variety of nitrogen-containing conjugated secondary ligands also can be combined,we can systematically use these novel poly-triazole ligands to build these novel multi-functional porous/chiral spin transition materials. Because of the use of these rigid/flexible bridging units and the introduction of various functional groups into triazole moieties, it can be more flexible to adjust its spin transition properties of these materials(such as transition temperature, hysteresis loop width, etc.). We can explore the internal relations of ligand structure and the composition of these materials. Further the internal relations of the magnetic properties of these materials and the composition of these materials also can be investigated. We can also investigate temperature-induced, light-induced spin transition effect and the effect of the adsorption/transfer of guest molecules or ions on its spin transition phenomenon.We can further use the domain model,two level Ising-type model and regular solution model to obtain some thermodynamic parameters. The design and synthesis of these novel multi-functional porous/chiral materials should provide novel examples for further investigating the mechanism of spin transition phenomenon and provide new research synthetic ideas for novel molecular switching devices and molecular information storage materials.

自旋转换材料的研究是当前化学和材料科学研究的前沿领域，利用不同物理条件下磁性能的转换，其有望发展成新一代的分子开关器件和信息存储材料。研究表明三氮唑体系非常适合构筑自旋转换配合物。而随着对自旋转换现象研究的深入，结合多孔吸附性质或手性的新型多功能自旋转换材料展现了良好的研究和应用前景。本课题拟通过芳香、烷烃等刚性或柔性的桥联基团将多个三氮唑配体连接,系统研究利用多三唑类配体(某些为手性配体)来构筑具有高维骨架结构的新型多孔/手性自旋转换配合物，在配体的桥联或三唑单元上均可引入各种功能基团，可以更为灵活的调节其自旋转换性能(转换温度、回滞环宽度等)。 研究结构组成，探索配合物产生的自旋转换性质与配体的类型及配合物结构的内在联系，寻找研究体系中具有应用价值的复合型自旋转换材料，研究热致、光致效应和客体分子的吸附/移除对其磁学性质的影响,为新型自旋转换磁性材料的设计合成以及机理研究提供新思路。

本项目自 2014年 1 月启动以来，至今历时三年，本课题组按照项目所提出的实施内容开展研究工作，已经设计合成6-7个系列未见文献报道的 1,2,3- 和 1,2,4-多三氮唑类衍生物配体并对其进行分析表征。我们研究了配体取代基、溶剂、抗衡阴离子等对于多三氮唑类研究体系中铁(II)配合物磁学性质的影响，分析了不同配体的结构(分子结构和空间结构)对铁(II)配合物的空间构型以及配合物材料光磁性质的影响。同时我们也制备了具有同质多晶现象的偶氮双三唑类铁(II)配合物，首次研究了不同溶剂分子对0D,1D 以及2D铁(II)配合物框架之间进行动态结构转换调控，通过“单晶到单晶的转换”(SC-to-SC Transformation) 的方法调控了三唑-铁(II)配合物自旋转换磁学性质。另一方面我们也发现某些多三氮唑类多孔性MOFs材料对于环境污染物表现出很好的荧光识别效果，使得这些材料在环境保护领域的应用方面也展现了重要的应用前景。目前申请者以第一作者或通讯联系人发表SCI收录论文19篇，获得授权专利6项，其中影响因子大于3.0 的SCI收录论文12篇，某些论文发表在Chem. Eur. J., Inorg. Chem., Cryst. Growth & Des.,CrystEngComm, RSC Advances等刊物上。