Description of the metal-ligand bonding in f-element complexes: a DFT study including scalar relativistic effects

摘要

A comparative density functional study on metal-ligand (M-L) interaction has been performed on X_3-M-L (X = F, I; M = U, La, Nd: L = NH_3, NCCH_3, CO) and X_3-M-(CO)_2 species including scalar relativistic effects by means of the zero-order regular approximation (ZORA) hamiltonian. The role of the halogen atoms in modeling the M-L interactions is discussed for pi-acceptor ligands CO and NCCH_3 and for the sigma-donor NH_3. The fluoride counterions, compared with previous calculations on the iodide complexes, stabilize more tadraedral structure with longer M-L distances. Finally, the addition of a second ligand to the previous species has permitted a more complete discussion on the backbonding effects on the uranium complexes.