Spectroscopic, structural, and theoretical studies of actinide-chalcogen bonding continue to emerge in the quest to understand the fundamental role that metal-ligand covalency plays in minor actinide/lanthanide separations and actinide electronic structure. Like dithiophosphinates that show exceptionally high selectivity for Am3+ over lanthanides (i.e. S2PR21-), most of the S, Se, and Te ligands that have been studied with actinides are negatively charged. As a result, there are significant electrostatic contributions that influence the ligand bonding with actinide cations, which makes it difficult to tease out how variations to metal-ligand covalency contribute to solution binding affinities. To address this challenge, we have been exploring the coordination chemistry and bonding of neutral thioether and selenoether ligands to f-elements to evaluate systematic structural and spectroscopic variations as the identity of the chalcogen is changed. Given that the neutral actinide-chalcogen bonding interactions were expected to be weak (especially with Se and Te), we prepared new multidentate amine-bis(phenolate) ligands containing pendant heavy ethers. The harder amine-bis(phenolate) donor groups were selected to ensure that the ligand remains bound to the metal so that we can evaluate the local bonding affinity of the heavy ether even if it is hemilabile or too weak to bind to the metal on its own. Several new crystal structures with uranium will be presented along with supporting spectroscopic data. The aim of these studies is to provide the foundation necessary for future transuranic work, which will require more specialized radiological facilities and controls.

Coordination chemistry of uranium with thioethers and selenoethers: Investigation of neutral heavy donor binding to heavy metals

253rd National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.