A Coordination Chemistry Approach to the Synthesis of Single-Molecule Magnets

合成单分子磁体的配位化学方法

• 批准号: 1800252
• 负责人: Jeffrey Long
• 金额: $ 54万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-05-01 至 2021-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1800252&HistoricalAwards=false
• 关键词: Coordination; Chemistry; Approach; Synthesis; Single

In this project, funded by the Chemical Structure, Dynamic & Mechanism B Program of the Chemistry Division, Professor Jeffrey Long of the Department of Chemistry at the University of California, Berkeley is designing and synthesizing new single-molecule magnets. Single-molecule magnets are molecules that behave as nanoscale magnets at low temperatures and can display magnetic properties akin to both classical and quantum systems. A potential direct application of this work is in the fields of magnetic data storage, quantum computing, and spintronics, however the knowledge gained by understanding magnetic properties on the molecular level is applicable to a wide variety of magnetic materials. Single-molecule magnets typically only operate at very low temperatures (less than 60 K). The goal of this project is to synthesize new molecules which have even higher operating temperatures. The project lies at the interface of inorganic chemistry, coordination chemistry, and physics. Both Professor Long and the members of his group are active in disseminating their work to a broad scientific audience, and the graduate students in the group participate in programs which place them in local elementary and middle school classrooms for hands-on science lessons. Single-molecule magnets are molecules with magnetically bistable ground states. When thermal energy is small relative to the thermal barrier between these states the magnetic molecule can retain its magnetization in the absence of an applied field. The proposed research adopts three strategies to synthesize single-molecule magnets which operate at higher temperatures. The first is to design systems with enhanced magnetic anisotropy, which will increase the thermal barrier to magnetic relaxation. Highly axial coordination environments will be employed for both transition metal and lanthanide complexes to achieve higher magnetic anisotropy. The second strategy is to utilize strong magnetic coupling to mitigate the effect of relaxation processes which shortcut the thermal barrier. Both transition metal and lanthanide complexes will be coupled with radical bridging ligands that promote strong metal-radical magnetic exchange. For transition metal complexes, direct metal-metal interactions will also lead to strongly coupled magnetic centers. Additionally, mixed 3d-4f systems will be developed to take advantage of both the large magnetic anisotropy of the lanthanides and the strong exchange coupling of the transition metals. Finally, the third strategy will place magnetically anisotropic moieties in the rigid coordination environments of metal-organic frameworks. In this manner it may be possible to minimize the effects of low energy lattice vibrations in causing through-barrier magnetic relaxation pathways.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在这个项目中，由化学结构，动态和机制B计划资助，加利福尼亚大学化学系的杰弗里·朗（Jeffrey Long）教授正在设计和合成新的单分子磁铁。单分子磁铁是在低温下以纳米级磁体作用的分子，可以显示类似于经典和量子系统的磁性。这项工作的潜在直接应用是在磁性数据存储，量子计算和旋转基质的领域中，但是通过理解分子水平上的磁性所获得的知识适用于多种磁性材料。单分子磁铁通常仅在非常低的温度（小于60 K）下运行。该项目的目的是合成具有更高工作温度的新分子。该项目位于无机化学，协调化学和物理学的界面。 Long教授和他的小组成员都积极地将他们的工作传播给广泛的科学受众，小组的研究生参加了课程，将他们置于当地的小学和中学课堂上，参加动手科学课程。单分子磁铁是具有磁性基态的分子。当热能相对于这些状态之间的热屏障小时时，磁分子可以在没有施加场的情况下保留其磁化。拟议的研究采用了三种策略来合成在高温下运行的单分子磁铁。首先是设计具有增强的磁各向异性的系统，这将增加磁性松弛的热屏障。过渡金属和灯笼配合物将采用高度轴向的配位环境，以实现较高的磁各向异性。第二种策略是利用强磁耦合来减轻捷径捷径的松弛过程的效果。过渡金属和灯笼络合物都将与促进强大金属激进磁交换的根部桥接配体结合。对于过渡金属配合物，直接金属相互作用也将导致强烈耦合的磁心中心。此外，将开发混合的3D-4F系统来利用灯笼的大磁各向异性和过渡金属的强交换耦合。最后，第三个策略将在金属有机框架的刚性协调环境中磁性各向异性部分。通过这种方式，可以最大程度地减少低能晶格振动在引起雷神磁性松弛途径中的影响。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子和更广泛影响的评估来审查标准来通过评估来获得支持的。

项目成果

Structural, Electrochemical, and Magnetic Studies of Bulky Uranium(III) and Uranium(IV) Metallocenes

• DOI: 10.1021/acs.inorgchem.9b02719
• 发表时间: 2019-12-16
• 期刊: INORGANIC CHEMISTRY
• 影响因子: 4.6
• 作者: Boreen, Michael A.;Lussier, Daniel J.;Arnold, John
• 通讯作者: Arnold, John

Access to Heteroleptic Fluorido‐Cyanido Complexes with a Large Magnetic Anisotropy by Fluoride Abstraction

通过氟化物提取获得具有大磁各向异性的杂配氟氰基配合物

• DOI: 10.1002/anie.201914934
• 发表时间: 2020
• 期刊: Angewandte Chemie International Edition
• 作者: Liu, Jun‐Liang;Pedersen, Kasper S.;Greer, Samuel M.;Oyarzabal, Itziar;Mondal, Abhishake;Hill, Stephen;Wilhelm, Fabrice;Rogalev, Andrei;Tressaud, Alain;Durand, Etienne
• 通讯作者: Durand, Etienne

A linear cobalt(II) complex with maximal orbital angular momentum from a non-Aufbau ground state

• DOI: 10.1126/science.aat7319
• 发表时间: 2018-12-21
• 期刊: SCIENCE
• 影响因子: 56.9
• 作者: Bunting, Philip C.;Atanasov, Milian;Long, Jeffrey R.
• 通讯作者: Long, Jeffrey R.

Synthesis and Magnetism of Neutral, Linear Metallocene Complexes of Terbium(II) and Dysprosium(II)

• DOI: 10.1021/jacs.9b05816
• 发表时间: 2019-08-21
• 期刊: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
• 影响因子: 15
• 作者: Gould, Colin A.;McClain, K. Randall;Long, Jeffrey R.
• 通讯作者: Long, Jeffrey R.

Substituent Effects on Exchange Coupling and Magnetic Relaxation in 2,2′-Bipyrimidine Radical-Bridged Dilanthanide Complexes

• DOI: 10.1021/jacs.0c10612
• 发表时间: 2020-12-16
• 期刊: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
• 影响因子: 15
• 作者: Gould, Colin A.;Mu, Edward;Long, Jeffrey R.
• 通讯作者: Long, Jeffrey R.