Controlling Magnetic Excitation Pathways via Molecular Design of Anisotropic Dipolar Spin Arrays

在化学部化学结构、动力学和机理B项目的支持下，加州大学圣地亚哥分校化学和生物化学系的杰弗里·D·莱因哈特和他的研究团队将致力于单分子水平上的磁性相互作用的设计。该团队的目标是一组特定的材料，这些材料通过直观和可控的机制相互作用，类似于普通的条形磁铁，尽管它们具有量子力学性质。获得这些新材料有可能为自下而上设计量子自旋相互作用提供新的途径。从该小组的研究中获得的见解将被用于磨练自旋弛豫的基本模型，并在量子信息科学中提供新的纠缠机制。这个项目结合了无机化学、有机化学、理论化学和计算化学，将主要由加州大学圣地亚哥分校的研究生和本科生进行。该项目范围内的推广活动将是与加州大学圣地亚哥分校普雷斯学校的合作，这是一所为初中和高中低收入学者设立的特许学校，目标是成为第一代大学生。控制高矩、高各向异性的镧系分子的自旋波函数需要广泛适用和可行的合成指南，以优化不同单位的期望磁性，并扩展到更高维度的材料。在这方面已经寻求了许多方法，包括优化晶场以最大化单离子各向异性，以及促进磁性金属中心之间的强轨道交换相互作用。强调控制性和通用性，这项工作试图通过基于高度各向异性单元之间的磁偶极子相互作用的积木方法来开发一种出现复杂性的一般策略。初步工作已经确定，当Er~(3+)与环辛四烯二阴离子结合时，磁取向各向异性是一致的和可预测的，从而留下其他配体位置来建立连接性。磁矩的可预测的大小和方向允许直观地设计通过空间的偶极相互作用路径。磁性建筑单元的人工可访问性和灵活性应该允许对分子结构进行严格控制，以修改、测试和描述跨对称、角度和维度参数空间的这种相互作用，为通过设计波函数方法研究分子自旋动力学创造了可能性。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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, Jeffrey D. Rinehart of the Department of Chemistry and Biochemistry at the University of California, San Diego and his research team will work toward the design of magnetic interactions at the single molecule level. The team is targeting a specific set of materials that interact via intuitive and controllable mechanisms akin to normal bar magnets, despite their quantum mechanical nature. Access to these new materials has the potential to offer new avenues to the design of quantum spin interactions from the bottom up. The insight garnered from the group’s research will be used to hone fundamental models of spin relaxation and offer new entanglement mechanisms in quantum information science. This project combines subjects of inorganic, organic, theoretical, and computational chemistry and will be conducted primarily by graduate and undergraduate students at University of California, San Diego. Outreach within the scope of this project will be a collaboration with the Preuss School UC San Diego, a charter school for middle and high school low-income scholars with goals to become first-generation college students. Controlling the spin wavefunction of high moment, high anisotropy lanthanide-based molecules requires broadly applicable and feasibly implementable synthetic guidelines both to optimize desired magnetic properties in distinct units and to extend into materials of higher dimensionality. Many approaches have been pursued in this regard, including optimizing the crystal field to maximize single-ion anisotropy and promoting strong orbital exchange interactions between magnetic metal centers. Emphasizing control and versatility, this work attempts to develop a general strategy to emergent complexity through a building block approach based on the magnetic dipolar interaction between highly anisotropic units. Preliminary work has established that magnetic orientational anisotropy is consistently and predictably enforced for an erbium ion (Er3+) when bound to a cyclooctatetraene dianion, leaving other ligand sites available to establish connectivity. The predictable magnitude and direction of the magnetic moment allow intuitive design of through-space dipolar interaction pathways. The synthetic accessibility and flexibility of the magnetic building unit should allow for tight control of molecular structure to modify, test, and describe this interaction across symmetry, angular, and dimensional parameter space, creating the potential for a wavefunction-by-design approach to molecular spin dynamics.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.