UC Santa Barbara

The understanding of reduction and remediation of uranyl (UO22+) in the environment is a crucial consideration when planning for storage of spent nuclear fuel, as uranyl is a water-soluble environmental contaminant. This dissertation will focus on the development of new synthetic methods for the reduction of uranyl(VI) to U(IV), utilizing a synergistic relationship between a silylating reagent and a reductant. These methods provide controlled one-pot transformations at ambient temperatures and pressures, where the fates of the substituted oxo ligands have been explicitly determined.

The uranyl moiety has a strictly linear O=U=O geometry, and a cis-uranyl ion is currently unknown. Isolating a cis-uranyl complex could provide some unique insights into actinide covalency and f-orbital participation in bonding. This dissertation discuses the coordination of small macrocycles to the uranyl fragment, which generates perturbed uranyl complexes with O-U-O bond angles ranging from 168° - 162°. These are some of the smallest O-U-O bond angles yet reported.