Uranocenium: Synthesis, Structure, and Chemical Bonding

ion of iodide from [(eta(5)-(C5Pr5)-Pr-i)(2)UI] (1) produced the cationic uranium(III) metallocene [(eta(5)-(C5Pr5)-Pr-i)(2)U](+) (2) as a salt of [B(C6F5)(4)](-). The structure of 2 consists of unsymmetrically bonded cyclopentadienyl ligands and a bending angle of 167.82 degrees at uranium. Analysis of the bonding in 2 showed that the uranium 5f orbitals are strongly split and mixed with the ligand orbitals, thus leading to non-negligible covalent contributions to the bonding. Investigation of the dynamic magnetic properties of 2 revealed that the 5f covalency leads to partially quenched anisotropy and fast magnetic relaxation in zero applied magnetic field. Application of a magnetic field leads to dominant relaxation by a Raman process.