空气稳定的高性能大环镝单离子磁体

Air‑stable High Performance Macrocyclic Dysprosium(Ⅲ)Single‑Ion Magnet

设计、合成空气稳定的高性能单分子磁体对实现单分子磁体在高密度信息存储、量子计算和分子自旋器件等方面的应用具有非常重要的意义。本文以镝离子为模板,通过N,N'-二(2-氨乙基)-1,3-丙二胺与2,6-二乙酰基吡啶原位缩合构筑了一个空气稳定的五角双锥构型的大环镝单离子磁体。单晶X射线衍射表明,镝离子处于赤道大环内部,其轴向位置被2个三苯基硅醇氧负离子占据,抗衡离子为四苯基硼负离子。静态磁性测试表明室温时该化合物的χ_(M)T值为13.96 cm^(3)·K/mol,接近单个自由镝离子的理论χ_(M)T值14.17 cm^(3)·K/mol,动态磁性测试表明,该化合物在零场下具有典型的单分子磁体行为,各向异性能垒高达1008 K。磁构关系研究表明,其优异的单分子磁体性能主要源于镝离子D_(5h)的局部对称性和三苯基硅醇氧负离子提供的强轴向型晶体场。另外,该化合物在空气中十分稳定,热重分析结果表明,其热分解温度高达297℃,为实现单分子磁体在导电基质表面的沉积打下基础。

Designing and preparing air-stable high-performance single-molecule magnets(SMMs)is of great significance toward the implementation of SMMs in high-density information storage,quantum computation and molecular-based spintronics devices.Herein,an air-stable macrocyclic Dy(Ⅲ)single-ion magnet with pentagonal bipyramidal local symmetry is obtained by the reaction between N,N'-bis(2-aminoethyl)-1,3-propanediamine and 2,6-diacetylpyridine with the dysprosium ion as template.Single crystal X-ray diffraction reveals that the dysprosium ion is encapsulated in the equatorial plane with BPh_(4)−as counter anion and the axial position is occupied by two Ph_(3)SiO−.The state magnetic measurements gives theχ_(M)T value of 13.96 cm^(·3) K/mol at room temperature,close to the theoretical value of 14.17 cm^(3)·K/mol for one isolated Dy(Ⅲ)ion.The dynamic magnetic measurements confirm its typical SMM behavior under a zero dc field with the effective magnetic reversal barrier up to 1008 K.Magneto-structural investigations show that the excellent SMM properties are attributed to the D_(5h) local symmetry and the strongly axial crystal field created by two Ph3SiO−for the dysprosium ion.Thermogravimetric analysis indicates that the compound is extremely air stable and the decomposition temperature reaches up to 297℃,which provides a promising avenue for depositing high performance SMMs on conductive substrate surfaces.