Influence of the nature of the ligands on the electronic ground state of organouranium (V) compounds, studied by electron paramagnetic resonance
Résumé
It is shown by electron paramagnetic resonance spectroscopy on a series of organouranium(V) compounds that interactions of uranium 5f orbitals with η8-C8H8, η5-C5H5, THF, and dialkylamide ligands are very weak. All of these ligands favor a predominantly $^{2}$F$_{5/2}$, MJ = ±1/2 metallic ground state, with an admixture of MJ = ±5/2. The presence of a THF ligand is characterized by an admixture of the MJ = ±3/2 states. Covalent interactions of 5f orbitals are much stronger with alkoxide ligands, so that J = 5/2 is no longer a good quantum number.