Trends in the Spin States and Mean Static Dipole Polarizability of the Group VIIIA Metallocenes

By using density functional theory, spin states, geometries, and mean static dipole polarizabilities of group VIIIA metallocenes M(C5H5)2 (M = Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, and Pt) are examined. For all metallocenes studied, comparison of the polarizability of the accessible spin states reveals that the lowest polarizability was found for the spin ground state. Therefore, our findings indicate that the minimum polarizability principle might be useful in determining the ground state multiplicity for transition metal metallocenes. The metallocenes from the group 8 and group 9 possess the same multiplicity, singlet and doublet, respectively. Additionally, one observes that the polarizability increases monotonically with the atomic number of the central metal atom for metallocenes from the same column. The B3LYP/ADZP is one of the most reliable procedure tested so far to predict the static dipole polarizability of the complexes studied here, with mean absolute deviation from the experimental data smaller than 1.8 au.