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The reactivity of the cationic gold carbide [AuC] + (bearing an electrophilic carbon atom) towards methane has been studied using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). The product pairs generated, that is, Au + /C 2 H 4 , [Au(C 2 H 2 )] + /H 2 , and [C 2 H 3 ] + /AuH, point to the breaking and making of C-H, C-C, and H-H bonds under single-collision conditions. The mechanisms of these rather efficient reactions have been elucidated by high-level quantum-chemical calculations. As a major result, based on molecular orbital and NBO-based charge analysis, an unprecedented hydride transfer from methane to the carbon atom of [AuC] + has been identified as a key step. Also, the origin of this novel mechanistic scenario has been addressed. The mechanistic insights derived from this study may provide guidance for the rational design of carbon-based catalysts., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

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., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The thermal reaction of diatomic tantalum nitride cation [TaN](+) with methane has been explored using FT-ICR mass spectrometry complemented by high-level quantum chemical calculation; based on this combined experimental/computational approach, mechanistic aspects of this novel, highly efficient C-N coupling process have been uncovered. In distinct contrast to [TaN](+) , its lighter congeners [VN](+) and [NbN](+) are inert towards methane under ambient conditions, and the origins of the remarkably variable efficiencies of the three metal nitrides are uncovered by CCSD(T) calculations., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The thermal reaction of [AuO](+) with methane has been explored using FT-ICR mass spectrometry complemented by high-level quantum chemical calculations. In contrast to the previously studied congener [CuO](+) , and to [AgO](+) , [AuO](+) reacts with CH4 exclusively via oxygen-atom transfer to form CH3 OH, and a novel mechanistic scenario for this selective oxidation process has been revealed. Also, the origin of the inertness of the [AgO](+) /CH4 couple has been addressed computationally., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The thermal reactions of methane with [HfO](.+) and [XHfO](+) (X=F, Cl, Br, I) were investigated by using FT-ICR mass spectrometry complemented by high-level quantum chemical calculations. Surprisingly, in contrast to the inertness of [HfO](.+) towards methane, the closed-shell oxide ions [XHfO](+) (X=F, Cl, Br) activate the H3 C-H bond to form the insertion products [Hf(X)(OH)(CH3 )](+) . The possible origin of this remarkable ligand effect is discussed., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Thermal reactions of the closed-shell metal-oxide cluster [TaO3 ](+) with methane were investigated by using FTICR mass spectrometry complemented by high-level quantum chemical calculations. While the generation of methanol and formaldehyde is somewhat expected, [TaO3 ](+) remarkably also has the ability to abstract two hydrogen atoms from methane with the elimination of CH2 . Mechanistically, the generation of CH2 O and CH3 OH occurs on the singlet-ground-state surface, while for the liberation of (3) CH2 , a two-state reactivity scenario prevails., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

High-level electronic structure calculations, in combination with Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometric studies, permit the mechanism by which closed-shell, "naked" [TaO2 ](+) brings about C-H bond activation of methane to be revealed. These studies also help to understand why the lighter congeners of [MO2 ](+) (M=V, Nb) are unreactive under ambient conditions., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The thermal reaction of [Ho(CH2S)](+) with toluene giving rise to [C6H5CHSHo](+) and CH4 has been investigated using Fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometry complemented by density functional theory (DFT) calculations. The high reactivity of [Ho(CH2S)](+) which is in distinct contrast with the non-reactivity of "bare" Ho(+) has its origin in the presence of a carbon-centered radical; the latter initiates hydrogen-atom abstraction from the methyl group of toluene as the first step of a sequence of hydrogen and sulfur transfer mediated by cationic holmium., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The thermal reactions of the closed-shell, "naked" gold-carbene complex [Au(CH2)](+) with methane have been explored by using FTICR mass spectrometry complemented by quantum chemical (QC) calculations at the CCSD(T)//BMK level of theory. Mechanistic aspects for this unprecedentedly efficient carbene insertion in the C-H bond of methane have been addressed and the origin of the counterintuitive high reactivity of [Au(CH2)](+) towards this most inert hydrocarbon is discussed., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The thermal reactions of the heteronuclear oxide cluster [Ga2 MgO4 ](.+) with methane and water have been studied using state-of-the-art gas-phase experiments in conjunction with quantum-chemical calculations. The significant reactivity differences, favoring activation of the strong OH bond, can be ascribed to a proton-coupled electron transfer (PCET) mechanism operative in the activation of water. This study deepens our mechanistic understanding on how inert RH bonds are cleaved by metal oxides., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Mechanistic insight into the homolytic cleavage of the O-H bond of water by the heteronuclear oxide cluster [Ga2 Mg2 O5 ](.+) has been derived from state-of-the-art gas-phase experiments in conjunction with quantum chemical calculations. Three pathways have been identified computationally. In addition to the conventional hydrogen-atom transfer (HAT) to the radical center of a bridging oxygen atom, two mechanistically distinct proton-coupled electron-transfer (PCET) processes have been identified. The energetically most favored path involves initial coordination of the incoming water ligand to a magnesium atom followed by an intramolecular proton transfer to the lone-pair of the bridging oxygen atom. This step, which is accomplished by an electronic reorganization, generates two structurally equivalent OH groups either of which can be liberated, in agreement with labeling experiments., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The reactivity of the heteronuclear oxide cluster [Ga2 Mg2 O5 ](.+) , bearing an unpaired electron at a bridging oxygen atom (Ob (.-) ), towards methane and ethane has been studied using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). Hydrogen-atom transfer (HAT) from both methane and ethane to the cluster ion is identified experimentally. The reaction mechanisms of these reactions are elucidated by state-of-the-art quantum chemical calculations. The roles of spin density and charge distributions in HAT processes, as revealed by theory, not only deepen our mechanistic understanding of CH bond activation but also provide important guidance for the rational design of catalysts by pointing to the particular role of doping effects., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)