Elucidation of the Bonding in Low-Valent Organoactinide Species

在化学系化学合成项目的支持下，普渡大学化学系的Suzanne Bart教授正在研究低价有机锕系化合物中的键合。最重的元素是锕系元素，包括铀和钍。虽然这些元素在核能和处理，例如，核废料的化学性质远不如更轻、更常见的金属。甚至锕系金属可以形成的化学键的类型也没有很好的确定。该项目将制备新型铀和钍化合物，其中金属具有异常低的氧化态，并通过多个化学键与其他原子连接。这些知识对于区分这些元素与其他金属以实现化学分离以及发现未来独特的化学性质非常重要。本研究计划的一个重要目标是将锕系元素的用途和性质纳入高中，大学和研究生的课程。由于在处理锕系元素方面受过训练的化学家的平均年龄增加，因此必须培养国家需要的这一领域的下一代科学家。为此，该项目包括在f元素化学和推广组件，以教育该地区的高中生的研究生和本科生的培训。此外，还将开展一系列旨在帮助研究生心理健康的项目。本项目将探讨锕系化合物中的共价键合程度。该方法是进行合成，表征和还原铀和钍配合物的反应性，用于有机金属过程和小分子活化。具体目标包括合成具有不同空间和电子性质的取代基的U-氮族元素（Pn）单键和多键，并研究软供体配体对锕系元素电子结构和共价性的影响。还将探索从强还原剂形成新的钍（III）衍生物，因为钍通常以+4氧化态存在。这些未充分研究的化合物预计具有有趣的电子结构，这对于研究了解潜在的应用非常重要。建议的工作包括合成方法的开发，光谱分析，磁化测量和计算方法，以充分了解这些重要的和未充分探索的低价有机锕系化合物的电子结构和反应性。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

With support from the Chemical Synthesis Program of the Chemistry Division, Professor Suzanne Bart from the Department of Chemistry at Purdue University, is studying bonding in low valent organoactinide compounds. The very heaviest elements are the actinide elements and include uranium and thorium. Although these elements are very important in nuclear energy and in the handling of, e.g., nuclear waste, their chemistry is not understood nearly as well as that of lighter, more common metals. Even the types of chemical bonds that the actinide metals can form are not well established. This project will prepare new classes of uranium and thorium compounds where the metals have unusually low oxidation states and are attached to other atoms through multiple chemical bonds. This knowledge is important for differentiation of these elements from other metals to enable chemical separations, and for discovering future unique chemistries. An important goal of this research program is to integrate the uses and properties of the actinide elements into the curricula of high school, college, and graduate students. As the average age of chemists trained in handling actinide elements increases, it is essential to prepare the next generation of scientists in this area of national need. Toward this end, the project includes the training of graduate and undergraduate students in f-element chemistry and outreach components to educate high school students in the area. In addition, a series of programs aimed at aiding the mental health of graduate students will be conducted.This project will explore the degree of covalent bonding in actinide compounds. The approach is to perform synthesis, characterization, and reactivity of reduced uranium and thorium complexes for organometallic processes and small molecule activation. Specific aims include synthesizing U-pnictogen (Pn) single and multiple bonds with substituents that have varying steric and electronic properties, and to study the effect of soft donor ligands on actinide electronic structure and covalency. The formation of new thorium(III) derivatives from strong reducing agents will also be explored, as thorium is typically found in the +4 oxidation state. These understudied compounds are expected to have interesting electronic structures that will be important to study to understand potential applications. The work proposed includes synthetic methodology development, spectroscopic analysis, magnetization measurements and computational approaches to fully understand the electronic structure and reactivity of these important and underexplored low valent organoactinide compounds.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.