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.