化学学报 ›› 2020, Vol. 78 ›› Issue (1): 34-55.DOI: 10.6023/A19090330 上一篇    下一篇

综述

环形镧系分子簇合物的组装与单分子磁体性质

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
  • 收稿日期:2019-09-06 出版日期:2020-01-15 发布日期:2019-11-06
  • 通讯作者: 郑丽敏 E-mail:lmzheng@nju.edu.cn
  • 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:
    项目受国家科技部重点研发计划(Nos.2017YFA0303203,2018YFA0306004)和国家自然科学基金(No.21731003)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 Online:2020-01-15 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).

由于稀土离子具有很强的磁各向异性,近年来基于单核或多核稀土化合物的单分子磁体研究得到了人们广泛的关注.环形簇合物是一类特殊的簇合物,也称分子轮或金属冠醚.设计合成环形稀土簇合物不仅可以获得新的稀土单分子磁体,而且环形簇合物中稀土离子磁偶极的涡旋分布还可以产生环形磁矩,因而在量子计算、信息存储、自旋分子器件等方面具有潜在的应用.鉴于环形稀土簇合物特别是含奇数核的环形簇合物的合成依然充满挑战,本综述将着重阐述已报道的环形稀土簇合物的组装规律、结构特点及磁性研究.

关键词: 单分子磁体, 稀土, 环形簇合物, 自组装

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