Acta Chimica Sinica ›› 2020, Vol. 78 ›› Issue (1): 34-55.DOI: 10.6023/A19090330 Previous Articles     Next Articles



田海权a,b, 郑丽敏a   

  1. a 南京大学化学化工学院 配位化学国家重点实验室 人工微结构协同创新中心 南京 210023;
    b 聊城大学化学化工学院 化学储能与新型电池技术省重点实验室 聊城 252059
  • 投稿日期:2019-09-06 发布日期:2019-11-06
  • 通讯作者: 郑丽敏
  • 作者简介:田海权,博士,讲师.南京大学化学化工学院2014级博士研究生,2017年7月加入聊城大学化学化工学院化学储能与新型电池技术省重点实验室,研究方向为稀土及稀土-过渡单分子磁体;郑丽敏,南京大学化学化工学院教授、博士生导师,2002年入选教育部跨世纪优秀人才培养计划,2003年获得国家自然科学基金会杰出青年基金.主要研究兴趣:功能金属有机膦酸材料、分子基光磁材料和离子导体等.
  • 基金资助:

Cyclic Lanthanide-based Molecular Clusters: Assembly and Single Molecule Magnet Behavior

Tian Haiquana,b, Zheng Li-Mina   

  1. a State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210023;
    b Shandong Provincial Key Laboratory of Chemical Energy Storage and Novel Cell Technology, School of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng 252059
  • Received:2019-09-06 Published:2019-11-06
  • Supported by:
    Project supported by the National Key R&D Program of China (Nos. 2017YFA0303203, 2018YFA0306004) and the National Natural Science Foundation of China (No. 21731003).

Lanthanide-based single molecule magnets have received tremendous attentions in recent years owing to the strong magnetic anisotropies of the lanthanide ions arising from the strong spin-orbital couplings. Cyclic metal clusters, also called molecular wheels or metallacrown ether, are a subclass of metal clusters. From the magnetic point of view, cyclic transition metal clusters can be devided into three types, e.g. ferromagnetically coupled cyclic clusters which favor single molecule magnet behavior, and antiferromagnetically coupled even-or odd-numbered cyclic clusters with S=0 or S=1/2 ground state. The magnetic properties of lanthanide-based cyclic clusters are more complicated because the magnetic interactions between the lanthanide ions are extremely weak. The overall magnetic behavior is largely dominated by the single ion anisotropy and the dipole-dipole interactions between the metal ions. When the anisotropy axes of the lanthanide ions in the cyclic clusters are arranged in a toroidal manner, single-molecule toroics could be achieved. Therefore, the design and synthesis of cyclic lanthanide-based clusters can provide not only new materials with architectural beauty and single molecule magnet behavior, but also single-molecule toroics with vortex distribution of the magnetic dipoles of lanthanide ions, which would have potential applications in information storage, quantum computing, spintronic devices and multiferroic materials. Noting that lanthanide-based single-molecule toroics have been described detailly in several reviews, this article will summarize the current status of the cyclic lanthanide clusters with the focus on the design and assembly strategies, the structural characteristics and magnetic studies. Most work have been concentrated on the Ln3, Ln4 and Ln6 cyclic clusters, including those containing oxygen centers. Examples of even-numbered cyclic clusters Lnx (x ≥ 8) are much less, and those of odd-numbered cyclic clusters Lnx (x ≥ 5) are rare. As the cyclic clusters are frequently distorted to different extent, many of them exhibit single molecule magnet behavior, and only few of them show toroic magnetization. It remains future challenges to design and synthesize new lanthanide-based cyclic clusters with regular and flat geometries and toroically arranged magnetic moments, and to achieve the multifunctions in the same molecular composite.

Key words: single molecule magnet, lanthanide, cyclic cluster, self-assembly