ELECTRONIC-STRUCTURES OF CYCLOBUTADIENE AND TRIMETHYLENEMETHANE

The photoelectron spectra of eight 4 π-electron hydrocarbons and their tricarbonyl complexes have been measured. From these spectra the perturbation energies of the π orbitals introduced by the tricarbonyliron moiety have been determined. These perturbation energies are 0.89 ± 0.07 and 0.22 ± 0.06 eV for the first and second π orbitals, respectively. Given these perturbation energies and the photoelectron spectra of the tricarbonyliron complexes of cyclobutadiene and trimethylenemethane, π-ionization energies for the two transients, cyclobutadiene (8.29 and 11.95 eV) and trimethylenemethane (8.36 and 11.79 eV), have been predicted. © 1967.