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

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 ' Am-3)(2)(mu - 4,4 '-bpy) and its lanthanide analogue, (Cp ' Nd-3)(2)(mu - 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. The coordination environment has a great impact on the electronic structure, bonding and properties of metal complexes. Here the authors report a dinuclear organometallic americium complex that displays unexpectedly ionic Am-N bonding, but enhanced covalency in the Am-C bonds compared to its neodymium analogue.

Automated summary

Variations in bonding and coordination environment in trivalent lanthanides and actinides can significantly affect their electronic structure and properties. A study reported a dinuclear organometallic americium complex with unexpectedly ionic Am-N bonding and enhanced covalency in the Am-C bonds compared to its neodymium analogue.