On the Activation of Methane and Carbon Dioxide by [HTaO]+ and [TaOH]+ in the Gas Phase: A Mechanistic Study

The thermal reactions of [Ta,O,H]+ with methane and carbon dioxide have been investigated experimentally and theoretically by using electrospray ionization mass spectrometry (ESI MS) and density functional theory calculations. Although the activation of methane proceeds by liberation of H2, the activation of CO2 gives rise to the formation of [OTa(OH)]+ under the elimination of CO. Computational studies of the reactions of methane and carbon dioxide with the two isomers of [Ta,O,H]+, namely, [HTaO]+ and [Ta(OH)]+, have been performed to elucidate mechanistic aspects and to explain characteristic reaction patterns. Double‐acting isomers: A combination of density functional theory calculations and mass spectrometric investigations shows that [Ta(OH)]+ and [HTaO]+ ions are capable of activating CH4 and CO2, by H2 elimination and decarbonylation, respectively (see figure).