Synthesis, Characterization, and Reactivity Studies of Cerium, Thorium, and Uranium-Ligand Multiple Bonds

在化学系化学合成项目的支持下，宾夕法尼亚大学的Eric Schelter教授正在研究铈、钍和铀化合物的化学性质。他的团队正在测试这些金属与氮和磷形成化学键的新方法。所得到的化合物将被评估其与含氮和含磷药物和新材料生产的相关性。该项目特别关注的是如何构建有机支架，以稳定新型键的方式包裹金属。通过比较各种铈、钍和铀化合物的结构，获得了对新键模式的指导和见解。稀土材料广泛应用于催化剂、荧光粉和抛光化合物，以及电子设备上的照明屏幕和空气污染控制。Schelter教授负责管理一个实验室，该实验室为研究生和本科生提供稀土元素合成和反应性的理论和实践实验培训。这项工作支持面向小学生和中学生的拓展项目；向年轻学生讲授稀土元素的技术和战略重要性。在化学系化学合成项目的支持下，宾夕法尼亚大学的Eric Schelter教授领导了一个旨在理解铈配体多键的项目。该研究将利用光谱学和计算方法建立它们的d/f键模式和电子结构。与5f元素同系物的比较反应性研究将提供对化学键的基本见解。中心假设是，控制铈（IV）键中相对较大的5d-特征将能够分离出新的金属配体多键例子。将合成铈、钍和铀-杂原子多键，如氮化物、膦嘧啶等，并比较它们的电子结构。建立了铈配体多键的反应模式。从研究中开发的基础知识有望证明如何理解元素周期表关键d-f界面上的元素键合，以及如何利用它们的化学和反应性来实现新的应用。稀土材料广泛应用于催化剂、荧光粉和抛光化合物，以及电子设备上的照明屏幕和空气污染控制。推进稀土化学，开发钍和铀的新型独特化学反应，有助于改善这些元素的选矿和分离，从而有助于国家安全，因为这些元素中有许多不在美国开采。本项目支持对高中生进行稀土元素重要性的教育。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 Synthesis Program in the Chemistry Division, Professor Eric Schelter at the University of Pennsylvania is investigating the chemistry of cerium, thorium, and uranium compounds. His team is testing new ways that these metals form chemical bonds to nitrogen and phosphorus. The resulting compounds will be evaluated for their relevance to the production of nitrogen- and phosphorus-containing pharmaceuticals and new materials. The project is particularly focused on ways that organic scaffolds can be build to wrap around the metals in ways that stabilize new kinds of bonds. Guidance and insight into the new bonding patterns are obtained by comparing the structures of the various cerium vs thorium vs uranium compounds. Rare earth materials are used extensively in diverse applications such as catalysts, phosphors and polishing compounds as well as for illuminated screens on electronic devices and air pollution control.Professor Schelter supervises a laboratory that provides graduate and undergraduate students with both theoretical and hands-on experimental training in the synthesis and reactivity of the rare earth elements. The effort supports outreach projects for elementary and high school students; Young students are instructed about the technology and strategic importance of rare earth elements.With support from the Chemical Synthesis Program in the Chemistry Division, Professor Eric Schelter at the University of Pennsylvania leads a program aimed at understanding cerium-ligand multiple bonds. The research will establish their d/f bonding patterns and electronic structures using spectroscopy and computation. Comparative reactivity studies with 5f-element congeners will provide fundamental insights into chemical bonding. The central hypothesis is that control of the relatively large 5d- character in the bonding of cerium(IV) will enable isolation of new examples of metal-ligand multiple bonds. Cerium, thorium, and uranium-heteroatom multiple bonds such as nitrides, phosphinidines, and others will be synthesized and their electronic structures compared. Reactivity patterns for cerium-ligand multiple bonds will be established. The fundamental knowledge developed from the research is expected to demonstrate how bonding of elements at the key d-f interface of the periodic table could be understood, and how their chemical and reactivity properties can be leveraged for new applications. Rare earth materials are used extensively in diverse applications such as catalysts, phosphors and polishing compounds as well as for illuminated screens on electronic devices and air pollution control. Advancing the chemistry of rare earths and developing new and distinctive chemical reactions for thorium and uranium contributes to improving beneficiation and separations of those elements, and therefore national security as many of these elements are not mined in the US. This project supports instruction of high school students about the importance of rare earth elements.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.