Expanding the Chemistry of Cerium and Uranium in their Highest Oxidation States: Electronic Structure, Redox and Organometallics

化学合成（SYN）计划的这项研究奖支持宾夕法尼亚大学的Eric Schelter教授合成分子铈和铀化合物的工作。铈氧化物作为活性载体在多相催化中有着广泛的应用。这些载体的应用范围从汽车催化转化器到氢气的生产。分子铈和铀化合物的知识将潜在地有助于新材料和设备的开发，如固体氧化物燃料电池。铈和铀的新应用也将增加轻稀土矿的经济价值，因为这些元素在国内稀土金属储量中很丰富。由于稀土材料广泛用于可再生能源技术以及雷达和航空电子等军事应用，预计国内镧系元素产量的增加将有助于国家安全。除了培养研究生和本科生，Schelter教授还与化学遗产基金会合作，提高公众对镧系元素和锕系元素重要性的认识。最高氧化态的分子铈和铀化合物的合成将支持其独特的电子结构，键合和反应性的研究。支持铈（IV）阳离子的配体的特性将使用电化学和密度泛函理论进行鉴定。这些知识将被应用于制备强稳定的铈（IV）化合物，包括有机金属化合物。具有轴对称性的铀（V）和铀（VI）化合物将通过新颖的多电子反应制备。将评价铀化合物的电子结构和物理化学特性，以确定金属配体共价性的特征。对小分子基板制备的新化合物的反应性将被探测和对比过渡金属，锕系元素和镧系元素的对应物。

This research award in the Chemical Synthesis (SYN) program supports work by Professor Eric Schelter at the University of Pennsylvania to synthesize molecular cerium and uranium compounds. Cerium oxides are used broadly as active supports in heterogeneous catalysis. Applications of these supports range from automotive catalytic converters to the production of hydrogen gas. Knowledge of molecular cerium and uranium compounds will potentially contribute to new materials and device development such as solid oxide fuel cells. New applications of cerium and uranium will also add economic value to light rare earth ores, given the abundance of those elements in domestic reserves of rare earth metals. Since rare earth materials are used broadly in both renewable energy technology, and military applications such as radar and avionics, the increased production of lanthanides domestically is expected to contribute to national security. In addition to training graduate and undergraduate students, Professor Schelter works with the Chemical Heritage Foundation to raise public awareness on the importance of lanthanides and actinides.The syntheses of molecular cerium and uranium compounds in their highest oxidation states will support studies of their unique electronic structures, bonding and reactivity. The characteristics of ligands that support cerium(IV) cations will be identified using electrochemistry and density functional theory. That knowledge will be applied to prepare strongly stabilized cerium(IV) compounds including organometallics. Uranium(V) and uranium(VI) compounds with axial symmetry will be prepared through novel multi-electron reactions. The electronic structures and physicochemical characteristics of the uranium compounds will be evaluated for signatures of metal-ligand covalency. The reactivity of the new compounds prepared toward small molecule substrates will be probed and contrasted with transition metal, actinide and lanthanide counterparts.