The low-lying cationic hole-states of η3-allyl tetracarbonyl complexes of Mn and Re

Abstract

The electronic structure in the ground state and the low-lying cationic hole states in a series of six η3-allyl transition metal tetracarbonyl complexes with Mn and Re has been studied by means of molecular orbital calculations and by means of He(I) photoelectron spectroscopy. The computational framework is a semiempirical INDO model. The ionization energies are calculated by means of the Green's function formalism with a second order and a renormalized self-energy approximation. Significant differences in the localization properties of the outer valence orbitals lead to a large deviation in the calculated reorganization energies. Koopmans' theorem is invalid in the manganese series. The interrelation between simple fragment molecular orbital models for transition metal complexes and the nature of the low-lying hole states is analysed.