Non-empirical valence-electron calculations on ethylene complexes of silver(I) and palladium(0)

Abstract

Non-empirical valence-electron calculations have been made on the complexes [Ag(C₂H₄)]⁺ and [Pd(C₂H₄)_n](n= 1, 3, or 4). The conclusion of earlier ab-initio calculations on [Ag(C₂H₄)]⁺ that donation of electrons from ethylene π to Ag 5s and 5p orbitals is the dominant bonding feature is confirmed. For the palladium(0) complexes, electron transfer occurs mainly from Pd to ethylene with both σ* and π* orbitals accepting electrons. A Mulliken-population analysis shows that the net charge residing on the ligands has a greater component in σ than in π orbitals. The important role of σ* orbitals in the bonding provides an explanation of why C₂F₄ complexes are more stable than C₂H₄.