On the Origin of Room-temperature, Au+-mediated Coupling of a Methylene Ligand with H2. Implications for the Mechanism of Methane Dehydrogenation

According to state-of-the-art computations, in conjunction with mass-spectrometric experiments, both the Au+-mediated, thermal coupling of a methylene ligand with molecular hydrogen as well as the activation of methane by atomic Au+ proceed through well-defined intermediates. The crucial transition state in the [Au(CH2)](+)/H-2 reversible arrow [Au( CH4)](+) conversion is, in many ways, reminiscent of the isolobal, thoroughly studied [CH3](+)/ H-2 reversible arrow [CH5](+) system. The previously suggested direct mechanism, according to which the Lewis acidity of Au+ alone accounts for the unusual behavior of the Au+/CH4 couple, has been modified.