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

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 = NH3, NCCH3, 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 NCCH3 and for the sigma-donor NH3. The fluoride counterions, compared with previous calculations on the iodide complexes, stabilize more tedraedral 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. (C) 2002 Wiley Periodicals, Inc.