Nature of the metalligand bond in trivalent neodymium complexes with neutral π-donor ligands. A theoretical study

The nature of bonding and energetics in trivalent rare earth π-donor ligand complexes [NdC13–πL] and [NdCp2–πL]+ have been investigated theoretically by employing Hartree–Fock (HF) and density functional theory (DFT) based methods. Acetylene, ethylene, butadiene, and benzene served as model π-ligands. Geometries and binding energies are reported. The analysis presented in this study clearly indicates the essentially electrostatic character of that binding interaction in terms of a cation–π-ligand interaction. The lanthanide to π-ligand bonding was predicted to be weak, accompanied with a slight distortion of the ligandʹs geometry upon coordination. The role of electron correlation does not appear to be crucial in correctly predicting the metal–ligand interaction energy and the ligand distortion.