Ab initio study of the photoelectron spectra and bonding in [Ru2(O2CH)4] and [Ru2(O2CH)4(NO)2]: the effect of axial ligands on metal-metal interactions

Abstract

Ab initio calculations at the self-consistent field level have been carried out on [Ru₂(O₂CH)₄] and [Ru₂(O₂CH)₄(NO)₂]. The ground-state configuration of [Ru₂(O₂CH)₄] is predicted to be σ²π⁴δ²δ*²π*² with the σ²π⁴δ²π*³δ* configuration being 15 kcal mol^–1 higher in energy. The metal ionization energies of both molecules have been calculated by a configuration-interaction method and provide an interpretation of the experimental photoelectron spectra consistent with measured intensity changes using He I and He II radiation.