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The study of chemical reactions between gold-containing heteronuclear oxide clusters and small molecules can provide molecular level mechanisms to understand the excellent activity of gold supported by metal oxides. While the promotion role of gold in alkane transformation was identified in the clusters with atomic oxygen radicals (O(-.)), the role of gold in the systems without O(-.) is not clear. By employing mass spectrometry and quantum chemistry calculations, the reactivity of Au2 VO3(+) clusters with closed-shell electronic structures toward ethane was explored. Both the dehydrogenation and ethene elimination channels were identified. It is gold rather than oxygen species initiating the C-H activation. The Au-Au dimer formed during the reactions plays important roles in ethane transformation. The reactivity comparison between Au2 VO3(+) and bare Au2(+) demonstrates that Au2 VO3(+) not only retains the property of bare Au2(+) that transforming ethane to dihydrogen, but also exhibits new functions in converting ethane to ethene, which reveals the importance of the composite system. This study provides a further understanding of the reactivity of metal oxide supported gold in alkane activation and transformation., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Investigations on the reactivity of atomic clusters have led to the identification of the elementary steps involved in catalytic CO oxidation, a prototypical reaction in heterogeneous catalysis. The atomic oxygen species O(.-) and O(2-) bonded to early-transition-metal oxide clusters have been shown to oxidize CO. This study reports that when an Au2 dimer is incorporated within the cluster, the molecular oxygen species O2 (2-) bonded to vanadium can be activated to oxidize CO under thermal collision conditions. The gold dimer was doped into Au2 VO4 (-) cluster ions which then reacted with CO in an ion-trap reactor to produce Au2 VO3 (-) and then Au2 VO2 (-) . The dynamic nature of gold in terms of electron storage and release promotes CO oxidation and O-O bond reduction. The oxidation of CO by atomic clusters in this study parallels similar behavior reported for the oxidation of CO by supported gold catalysts., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The first example of a metal oxide cluster anion, La6 O10 (-) that can activate methane under ambient conditions is reported. This reaction is facilitated by the oxygen-centered radical (O(-⋅) ) and follows the hydrogen atom transfer mechanism. The La6 O10 (-) has a high vertical electron detachment energy (VDE=4.06 eV) and a high symmetry (C4v )., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The activation of C-H bonds in alkanes is currently a hot research topic in chemistry. The atomic oxygen radical anion (O(-·)) is an important species in C-H activation. The mechanistic details of C-H activation by O(-·) radicals can be well understood by studying the reactions between O(-·) containing transition metal oxide clusters and alkanes. Here the reactivity of scandium oxide cluster anions toward n-butane was studied by using a high-resolution time-of-flight mass spectrometer coupled with a fast flow reactor. Hydrogen atom abstraction (HAA) from n-butane by (Sc2O3)(N)O(-) (N=1-18) clusters was observed. The reactivity of (Sc2O3)(N)O(-) (N=1-18) clusters is significantly sizedependent and the highest reactivity was observed for N=4 (Sc8O13(-)) and 12 (Sc24O37(-)). Larger (Sc2O3)(N)O(-) clusters generally have higher reactivity than the smaller ones. Density functional theory calculations were performed to interpret the reactivity of (Sc2O3)(N)O(-) (N=1-5) clusters, which were found to contain the O(-·) radicals as the active sites. The local charge environment around the O(-·) radicals was demonstrated to control the experimentally observed size-dependent reactivity. This work is among the first to report HAA reactivity of cluster anions with dimensions up to nanosize toward alkane molecules. The anionic O(-·) containing scandium oxide clusters are found to be more reactive than the corresponding cationic ones in the C-H bond activation., (Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)