Efficient Room-Temperature Methane Activation by the Closed-Shell, Metal-Free Cluster [OSiOH](+) : A Novel Mechanistic Variant.
The closed-shell cluster ion [OSiOH](+) is generated in the gas phase and its reactivity towards the thermal activation of CH4 has been examined using Fourier transform-ion cyclotron resonance (FT-ICR) mass spectrometry in conjunction with state-of-the-art quantum chemical calculations. Quite unexpectedly at room temperature, [OSiOH](+) efficiently mediates C-H bond activation, giving rise to [SiOH](+) and [SiOCH3 ](+) with the concomitant formation of methanol and water, respectively. Mechanistic aspects for this unprecedented reactivity pattern are presented, and the properties of the [OSiOH](+) /CH4 couple are compared with those of the closed-shell systems [OCOH](+) /CH4 and [MgOH](+) /CH4 ; the last two couples exhibit an entirely different reactivity scenario.