CAREER: Design Strategies for High-Performance Bismuth- and Lanthanide-Based Single-Molecule Magnets

密歇根州立大学化学系的Selvan Demir在化学系化学结构、动力学和机理b项目的支持下，利用有机金属化学来开发具有有趣磁性的新型分子化合物，即单分子磁体（SMMs）。smm令人兴奋的潜在应用范围从高密度信息存储，量子计算到基于自旋的电子设备，但取决于增加自旋逆转势垒，磁阻塞温度和强制场-所有描述分子在去除施加的外部磁场后保留信息的能力的指标。该项目将开发新的合理设计策略，以产生包含铋和顺磁性镧系元素的新型smm。铋和镧系位点的电子特性的结合可以带来具有无与伦比的性能特征的新一代smm。该项目以多种方式将学术研究和教育紧密结合，为公众和学生提供最高水平的教育。这包括一种创造性的方法“科学遇见艺术”，利用可视化的力量，促进进入精心设计的基于旋转的科学主题，在画廊和博物馆计划展览。在当地学校的讲座中，还开发了一门带有磁性工具包的实验性量子信息科学课程。单分子磁体（SMMs）表现出自旋逆转的障碍，并且在没有量子隧道的情况下，类似于体磁体的磁滞。因此，同时提高自旋基态和磁各向异性是研究强耦合多核smm的关键目标之一，也是具有挑战性的目标之一。强耦合抑制了高温smm所需的量子隧道等快速弛豫途径，因此需要强耦合。此外，必须探索新的化学空间来推进该领域。因此，本项目旨在开发新的合理设计策略，以产生(i)第一个以铋为中心的smm， （ii）含有铋自由基的新型镧系smm， （iii）由铋和氮供体组成的新型氧化还原活性杂环配体，（iv）由铋-氮杂环桥组成的第一个多核smm，以及(v)第一个含有铋-氮杂环自由基的多核smm。从基本的角度来看，通过抗磁性和顺磁性桥的磁耦合途径的深入研究有可能推进SMM中发生的弛豫动力学的知识，从而为未来的SMM设计铺平道路。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 Program of the Chemistry Division, Selvan Demir of the Department of Chemistry at Michigan State University is employing organometallic chemistry to develop new classes of molecular compounds with interesting magnetic properties, known as single-molecule magnets (SMMs). The exciting potential applications of SMMs span from high-density information storage, quantum computing, to spin-based electronic devices, but hinge on increasing the spin-reversal barrier, magnetic blocking temperature, and coercive field - all metrics that describe the molecule’s ability to retain information after removing an applied external magnetic field. This project will develop new rational design strategies to engender new types of SMMs comprising bismuth and the paramagnetic lanthanides. The combination of the electronic features of bismuth and lanthanide sites could usher in a new generation of SMMs with unparalleled performance characteristics. The project tightly integrates academic research and education in several ways to provide the highest level of education to the public and students at all stages. This includes a creative approach “Science Meets Art” that utilizes the power of visualization to facilitate entry into the elaborate spin-based science subject where exhibitions in a gallery and museums are planned. The development of an experimental quantum information science course accompanied with a magnetism kit is also encompassed alongside lectures at local schools.Single molecule magnets (SMMs) exhibit a barrier to spin reversal and in the absence of quantum tunneling, magnetic hysteresis similar to bulk magnets. Therefore, one of the most important but also challenging goals is to increase simultaneously spin ground state and magnetic anisotropy, critical goals in the pursuit of strongly coupled multinuclear SMMs. Strong coupling is required as it suppresses fast relaxation pathways such as quantum tunneling which is needed for high-temperature SMMs. In addition, new chemical space must be explored to advance the field. Accordingly, this project aims to develop new rational design strategies to engender (i) the first bismuth-centered SMMs, (ii) new lanthanide SMMs containing bismuth radicals, (iii) new redox-active heterocyclic ligands composed of bismuth and nitrogen donors, (iv) the first multinuclear SMMs consisting of bismuth-nitrogen heterocyclic bridges, and (v) the first multinuclear SMMs containing bismuth-nitrogen heterocyclic radicals. From a fundamental point of view, the thorough study of magnetic coupling pathways through diamagnetic and paramagnetic bridges has the potential to advance knowledge of relaxation dynamics occurring in SMMs, and in so doing, pave the way for future SMM design.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.