2CH4 + 1/2O2 → C2H6 + H2O Equation 1. Homolytic cleavage of the C–H bond is viewed as the key step in the oxidative coupling of methane. State-of-the-art gas-phase experiments in conjunction with computational studies permit the elucidation of mechanistic details of the hydrogen-atom transfer (HAT) by metal oxides. Two distinct mechanistic variants have been identified. The first one corresponds to a direct pathway (“harpoon” mechanism) from the hydrocarbon to the abstracting oxygen atom; the second mode involves several steps including a metal-mediated step to form a metal-carbon bond. Various examples for either scenario will be presented. In addition, mechanistic implications are discussed which pertain to heterogeneous catalysis as well as enzymatic processes. Finally, the crucial role of unpaired spin density at the abstracting atom will be demonstrated.1 (1) Schwarz, H. Isr. J. Chem., 2014, 54, 1413.

Thermal hydrogen-atom transfer from methane: A mechanistic exercise

249th National Meeting (2015)

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