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

在化学部化学结构、动力学和机理B （CSDM-B）项目的支持下，加州大学伯克利分校化学系的Jeffrey R. Long教授正在设计和合成新的单分子磁铁。在去除外加磁场后，这些物质显示出磁记忆的特征，这种特性长期以来被认为只出现在块状永磁材料的长程磁序中。然而，在单个纳米级分子中观察到这种行为是值得注意的，并可能导致高密度数据处理、量子信息科学和量子传感等领域的变革性进步。该项目位于合成分子化学和物理的交汇处，因此非常适合具有广泛兴趣的跨学科年轻科学家，并促进来自代表性不足背景的学生的参与。最后，一个拓展项目将寻求教育湾区K-12学生磁性分子在社会中的作用和奇迹。这项研究将采用基本的分子设计原理来合成新的单分子磁体，目标是用于高工作温度的系统。该项目将测试一个中心假设，即配位化学可以合成具有定制电子结构的分子，从而产生具有前所未有工作温度的单分子磁体。更具体地说，本提案侧重于设计和合成新的镧系和过渡金属基分子，具有(i)最大的轴向晶体场各向异性，以提供高弛豫势垒；（ii）强磁交换相互作用，以减轻有害的量子隧道效应。该项目将扩展我们对如何操纵分子中各种磁性质的知识，包括单离子磁各向异性、磁矫顽力和磁耦合相互作用。这个项目产生的基础知识可能会导致无数技术领域的进步，包括量子信息科学、超硬磁学和生物医学成像。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With support from the Chemical Structure, Dynamics & Mechanisms B (CSDM-B) Program of the Chemistry Division, Professor Jeffrey R. Long of the Department of Chemistry at the University of California, Berkeley, is designing and synthesizing new single-molecule magnets. Upon removal of an applied magnetic field, these species display signatures of magnetic memory, a property long thought to arise exclusively from long-range magnetic order in bulk permanent magnet materials. However, the observation of such behavior in individual nanoscopic molecules is remarkable and may lead to transformative advances in areas such as high-density data processing, quantum information science, and quantum sensing. This project lies at the interface of synthetic molecular chemistry and physics and is therefore ideally suited for interdisciplinary young scientists with broad interests and for promoting the inclusion of students from underrepresented backgrounds. Finally, an outreach program will seek to educate Bay Area K–12 students on the role and wonder of magnetic molecules in society.This research will employ fundamental molecular design principles to newly synthesize single-molecule magnets, aiming for systems with high operating temperatures. The project will test the central hypothesis that coordination chemistry can enable the synthesis of molecules with tailored electronic structures, thereby giving rise to single-molecule magnets with unprecedented operating temperatures. More specifically, this proposal focuses on the design and synthesis of new lanthanide- and transition metal-based molecules with (i) maximal axial crystal-field anisotropy to give high relaxation barriers and (ii) strong magnetic exchange interactions to mitigate deleterious quantum tunneling. This project will expand our knowledge of how to manipulate a wide range of magnetic properties in molecules, including single-ion magnetic anisotropy, magnetic coercivity, and magnetic coupling interactions. The fundamental knowledge generated from this project may lead to advances in myriad technological areas–including quantum information science, ultra-hard magnetism, and biomedical imaging.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.