A comparison of the electronic structure of some Group 6A dimetal tetracarboxylates using photoelectron spectroscopy

Abstract

He(I) and He(II) photoelectron spectra are presented for [Cr₂(O₂CR)₄](R = Me or Et), [CrMo(O₂CMe)₄], and [Mo₂(O₂CR)₄](R = H, Me, CMe₃, or CF₃). Ionization energies and intensities are discussed in relation to ab initio and SCF–Xα-SW calculations. A σ²π⁴δ² configuration for the metal electrons gives the most plausible explanation for all spectra, but the ²Σ, ²Π and ²Δ ion states lie much closer in energy for the dichromium tetracarboxylates than for the molybdenum analogues.