The He(I) photoelectron spectra and valence electronic structures of η⁵-C₅H₅Mn(CO)₂N₂ and η⁵-C₅H₅Mn(CO)₂NH₃

The He(I) photoelectron spectra of η⁵-C₅H₅Mn(CO)₂N₂ and η⁵-C₅H₅Mn(CO)₂NH₃ have been obtained. The general features of these spectra resemble those of the parent carbonyl complex, η⁵-C₅H₅Mn(CO)₃. The major differences appear in the ionizations associated predominantly with the metal d levels, where shifts in ionization energies and loss of degeneracy reflect the differences in bonding of the nitrogen ligands and a carbonyl ligand with the metal center. Non-empirical molecular orbital calculations were used as an aid for the interpretation of these binding energy shifts. In the case of N₂ bound to the metal, the shifts in ionization potentials are predicted with extreme accuracy by the shifts in eigenvalues of the calculations. Thus the electronic structure of transition metal dinitrogen complexes, as compared to carbonyl complexes, is accurately described. The quantitative prediction of binding energy shifts for the amine complex are less satisfactory, although the qualitative behavior is reproduced quite well.