Electronic structure of metal complexes containing π-cyclopentadienyl and related ligands. Part 1.—He(I) photoelectron spectra of some closed-shell metallocenes

The He(I) photoelectron spectra of ferrocene, 1,1′-dimethylferrocene, 1,1′-dichloroferrocene, ruthenocene, 1,1′-dimethylruthenocene, 1,1′-dimethylosmocene, bis(π-cyclopentadienyl)magnesium, bis(π-methylcyclopentadienyl)magnesium, and methylcyclopentadiene are reported and assigned using largely empirical arguments. The details of the spectra are discussed using a simple molecular orbital model and compared with the expectations of ligand field theory.