Metal-Free, Room-Temperature Oxygen-Atom Transfer in the N2 O/CO Redox Couple as Catalyzed by [Si2 Ox ].+ (x=2-5).

The thermal reduction of N2 O by CO mediated by the metal-free cluster cations [Si2 Ox ].+ (x=2-5) has been examined in the gas phase using Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry in conjunction with quantum chemical calculations. Three successive oxidation/reduction steps occur starting from [Si2 O2 ].+ and N2 O to form eventually [Si2 O5 ].+ ; the latter as well as the intermediate oxide cluster ions react sequentially with CO molecules to regenerate [Si2 O2 ].+ . Thus, full catalytic cycles occur at ambient conditions in the gas phase. Mechanistic aspects of these sequential redox processes have been addressed to reveal the electronic origins of these unparalleled reactions.