Gas-phase reactions of rhenium-oxo species ReOn+, n = 0, 2–6, 8, with O2, N2O, CO, H2O, H2, CH4 and C2H4

Abstract

The reactions of ReO_n⁺, n = 0, 2–6, 8, with the small molecules O₂, N₂O, CO, H₂O, H₂ , CH₄ and C₂H₄, are studied by Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry under single collision conditions on the timescale of seconds. The ReO_n⁺ species are produced by laser vaporization of solid rhenium and pulsed supersonic expansion in a helium–oxygen mixture into high vacuum. A wide variety of reactions are observed, including methane activation and epoxidation reactions. Re⁺ reacts with ethylene by sequential dehydrogenation. ReO₂⁺ and ReO₄⁺ exhibit the most diverse reaction pathways, while ReO₅⁺ almost exclusively undergoes ligand exchange. ReO₆⁺ and ReO₈⁺ are largely unreactive, the only efficient reactions observed are with ethylene and water. Both molecules seem to be able to directly attack the dioxygen ligands. The observed chemistry is governed by a fine interplay between available coordination sites and thermochemistry.