Chemical Triggers for Spin-State Switching: Discovery and Control of Switching Mechanisms

在该项目中，科罗拉多州立大学(CSU)化学系的Matthew Shores教授在化学系化学结构、动态和机理B计划的资助下，正在探索可用作分子开关的新型过渡金属络合物。这项研究的目的是了解主客体相互作用如何改变配位络合物的结构和改变它们的磁性。这些结果将为化学传感器、可切换分子磁体和磁共振造影剂的开发提供设计原则。该项目结合了几种综合、测量和计算技术，为参与其中的研究型学生提供多样化的培训。与CSU本科生化学研究经验项目的互动以及与CSU-Pueblo研究人员的合作旨在扩大代表不足的群体的参与。该小组在磁性测量和数据解释方面的专业知识将通过与全国各地的无机和材料化学研究小组进行的几个正在进行的和新的磁性合作来促进发现。可以存在于两个明确定义的磁性状态中并在两个明确定义的磁性状态之间可靠切换的络合物为纳米和分子长度尺度的功能材料开发提供了可能性。这项研究旨在通过外球与客体分子的非共价相互作用来控制局域几何结构和配位场效应，从而增强过渡金属络合物的磁性开关。这个项目的具体研究目标是：(1)计算理解磁态转换中的热力学和扭曲路径，走向预测模型；(2)探索与客体相关的自旋态转换络合物的新化学触发器和新离子；以及(3)Co(II)单分子磁性络合物中轴向磁各向异性的外部控制。最终目的是在磁性转换的新机制设计方面获得新的理解，并贡献与化学传感和分子成像应用相关的新传感架构。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。

In this project, funded by the Chemical Structure, Dynamic & Mechanism B Program of the Chemistry Division, Professor Matthew Shores of the Department of Chemistry at Colorado State University (CSU) is exploring new classes of transition metal complexes that can serve as molecular switches. The goal of the research is to understand how host-guest interactions alter the structure of coordination complexes and change their magnetic properties. These results will inform design principles for the development of chemical sensors, switchable molecular magnets, and magnetic resonance contrast agents. The project combines several synthetic, measurement and computational techniques to provide diverse training for the research students involved. Interactions with the CSU Chemistry Research Experiences for Undergraduates program and collaborations with researchers at CSU-Pueblo aim to broaden participation from underrepresented groups. The group's expertise in magnetic measurements and data interpretation will promote discovery via several ongoing and new magnetic collaborations with inorganic and materials chemistry research groups around the country.Complexes that can exist in and reliably switch between two well-defined magnetic states offer the possibility for functional materials development at the nano- and molecular length scales. The proposed research aims to enhance magnetic property switching in transition metal complexes by controlling local geometry and ligand field effects via outer sphere, non-covalent interactions with guest molecules. Specific research goals for this project are: (1) computational understanding of thermodynamics and distortion pathways in magnetic-state switching, toward predictive models; (2) exploration of new chemical triggers and new ions for guest-dependent spin-state switching complexes; and (3) external control of axial magnetic anisotropy in Co(II) single-molecule magnet complexes. The ultimate aim is to gain new understanding in the design of novel mechanisms for magnetic property switching, and contribute new sensing architectures relevant to chemical sensing and molecular imaging applications.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.