Cyclopentadienyl coordination induces unexpected ionic Am-N bonding in an americium bipyridyl complex

Nat Commun. 2022 Jan 11;13(1):201. doi: 10.1038/s41467-021-27821-4.

Abstract

Variations in bonding between trivalent lanthanides and actinides is critical for reprocessing spent nuclear fuel. The ability to tune bonding and the coordination environment in these trivalent systems is a key factor in identifying a solution for separating lanthanides and actinides. Coordination of 4,4'-bipyridine (4,4'-bpy) and trimethylsilylcyclopentadienide (Cp') to americium introduces unexpectedly ionic Am-N bonding character and unique spectroscopic properties. Here we report the structural characterization of (Cp'3Am)2(μ - 4,4'-bpy) and its lanthanide analogue, (Cp'3Nd)2(μ - 4,4'-bpy), by single-crystal X-ray diffraction. Spectroscopic techniques in both solid and solution phase are performed in conjunction with theoretical calculations to probe the effects the unique coordination environment has on the electronic structure.