He(I) photoelectron spectra of tetracarbonyliron complexes of Group 5 ligands and of olefinic ligands

Abstract

The photoelectron spectra of some five-co-ordinate trigonal-bipyramidal complexes [Fe(CO)₄L](L = PMe₃, PPh₃, AsPh₃, or pyridine in an axial position, or CH₂CH–CN and CH₂CH–CHO in the equatorial plane) have been measured. The spectra have been assigned by comparing them with one another and with those available for [Fe(CO)₅] and [Fe(CO)₄(η-C₂H₄)]. CNDO calculations carried out for [Fe(CO)₄(py)] and [Fe(CO)₄(η²-CH₂CH–CN)] are of only limited help in making assignments. The substituent effect on the stability of the Fe-L bond is discussed. The stability order obtained is the same as that found previously via kinetic studies.