Theoretical investigation of mixed-ligand lanthanocene complexes, (η5-C5H5)2LnX · OC4H8 (Ln=La, Gd, Lu; X=F, Cl, Br, I)

For the first time, density functional theory (DFT) calculation was performed on the titled complexes and the calculated geometries are in good agreement with the available experimental data. The decrease in the bond distances (Ln–X) as well as the increase in the Hirshfeld charges and the chemical hardness from La to Lu indicates an increase in ionic character on going from La to Lu. The lanthanide contraction and ionic character of metal–ligand bond are found to follow the order: Ln–X > Ln–Cp > Ln–O.