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

化学合成(SYN)项目的这项研究奖支持宾夕法尼亚大学的Eric Schelter教授合成分子Ce和铀化合物的工作。氧化铈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生产。对分子铈和铀化合物的了解可能会对固体氧化物燃料电池等新材料和设备的开发做出贡献。鉴于国内稀土金属储量中丰富的稀土元素，稀土和铀的新应用也将增加轻稀土矿石的经济价值。由于稀土材料在可再生能源技术以及雷达和航空电子等军事应用中广泛使用，预计国内稀土元素产量的增加将有助于国家安全。除了培训研究生和本科生外，Schelter教授还与化学传统基金会合作，提高公众对镧系元素和辐系元素重要性的认识。分子Ce3+和铀化合物在其最高氧化态的合成将支持对其独特的电子结构、成键和反应活性的研究。使用电化学和密度泛函理论来确定支持Ce(IV)离子的配体的特征。这些知识将被应用于制备包括有机金属在内的强稳定的Ce(IV)化合物。通过新颖的多电子反应，将制备出轴对称的铀(V)和铀(VI)化合物。将对铀化合物的电子结构和物理化学特征进行评估，以确定金属-配体共价性的特征。新合成的化合物对小分子底物的反应性将被探索，并与过渡金属、榄系元素和镧系元素的对应化合物进行对比。

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.