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

University Of Pennsylvania, Philadelphia PA

Investigators

Abstract

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.