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Transition-metal catalyzed coupling to form C-N bonds is significant in chemical science. However, the inert nature of N 2 and CO 2 renders their coupling quite challenging. Herein, we report the activation of dinitrogen in the mild plasma atmosphere by the gas-phase monometallic YB 1-4 - anions and further coupling of CO 2 to form C-N bonds by using mass spectrometry and theoretical calculation. The observed product anions are NCNBO - and N(BO) 2 - , accompanied by the formation of neutral products YO and YB 0-2 NC, respectively. We can tune the reactivity and the type of products by manipulating the number of B atoms. The B atoms in YB 1-4 N 2 - act as electron donors in CO 2 reduction reactions, and the carbon atom originating from CO 2 serves as an electron reservoir. This is the first example of gas-phase monometallic anions, which are capable to realize the functionalization of N 2 with CO 2 through C-N bond formation and N-N and C-O bond cleavage., (© 2022 Wiley-VCH GmbH.)

The mass-selected Fe 2 O + cation mediated propane oxidation by O 2 was investigated by mass spectrometry and density functional theory calculations. In the reaction of Fe 2 O + with C 3 H 8 , H 2 was liberated by C-H bond activation to give Fe 2 OC 3 H 6 + . Interestingly, when a mixture of C 3 H 8 /O 2 was introduced into the reactor, an intense signal that corresponded to the Fe 2 O 2 + cation was present; the experiments indicated that O 2 was activated in its reaction with Fe 2 O(C 3 H 6 ) + to give Fe 2 O 2 + and C 3 H 6 O (acetone or propanal). A Langmuir-Hinshelwood-like mechanism was adopted in the propane oxidation reaction by O 2 on gas-phase Fe 2 O + cations. In comparison with the absence of Fe 2 O 2 + in the reaction of Fe 2 O + with O 2 , the ligand effect of C 3 H 6 on Fe 2 OC 3 H 6 + is important in the oxygen activation reaction. The theoretical results are consistent with the experimental observations. The propane oxidation by O 2 in the presence of Fe 2 O + might be applied as a model for alkane and O 2 activations over iron oxide catalysts, and the mechanisms and kinetic data are useful for understanding corresponding heterogeneous reactions., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Atomic clusters are being actively studied for activation of methane, the most stable alkane molecule. While many cluster cations are very reactive with methane, the cluster anions are usually not very reactive, particularly for noble metal free anions. This study reports that the reactivity of molybdenum carbide cluster anions with methane can be much enhanced by adsorption of CO. The Mo2 C2 (-) is inert with CH4 while the CO addition product Mo2 C3 O(-) brings about dehydrogenation of CH4 under thermal collision conditions. The cluster structures and reactions are characterized by mass spectrometry, photoelectron spectroscopy, and quantum chemistry calculations, which demonstrate that the Mo2 C3 O(-) isomer with dissociated CO is reactive but the one with non-dissociated CO is unreactive. The enhancement of cluster reactivity promoted by CO adsorption in this study is compared with those of reported systems of a few carbonyl complexes., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Investigations of the intrinsic properties of gas-phase transition metal nitride (TMN) ions represent one approach to gain a fundamental understanding of the active sites of TMN catalysts, the activities and electronic structures of which are known to be comparable to those of noble metal catalysts. Herein, we investigate the structures and reactivities of the triatomic anions HNbN(-) by means of mass spectrometry and photoelectron imaging spectroscopy, in conjunction with density functional theory calculations. The HNbN(-) anions are capable of activating CH4 and C2H6 through oxidative addition, exhibiting similar reactivities to free Pt atoms. The similar electronic structures of HNbN(-) and Pt, especially the active orbitals, are responsible for this resemblance. Compared to the inert NbN(-), the coordination of the H atom in HNbN(-) is indispensable. New insights into how to replace noble metals with TMNs may be derived from this combined experimental/computational study., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Aluminum-vanadium bimetallic oxide cluster anions (BMOCAs) have been prepared by laser ablation and reacted with ethane and n-butane in a fast-flow reactor. A time-of-flight mass spectrometer was used to detect the cluster distribution before and after the reactions. The observation of hydrogen-containing products AlVO(5)H(-) and Al(x)V(4-x)O(11-x)H(-) (x=1-3) strongly suggests that AlVO(5)(-) and Al(x)V(4-x)O(11-x)(-) (x=1-3) can react with ethane and n-butane by means of an oxidative dehydrogenation process at room temperature. Density functional theory studies have been carried out to investigate the structural, bonding, electronic, and reactive properties of these BMOCAs. Terminal-oxygen-centered radicals (O(t)(.)) were found in all of the reactive clusters, and the O(t)(.) atoms, which prefer to be bonded with Al rather than V atoms, are the active sites of these clusters. All the hydrogen-abstraction reactions are favorable both thermodynamically and kinetically. To the best of our knowledge, this is the first example of hydrogen-atom abstraction by BMOCAs and may shed light on understanding the mechanisms of C−−H activation on the surface of alumina-supported vanadia catalysts., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Vanadium-silicon heteronuclear oxide cluster cations were prepared by laser ablation of a V/Si mixed sample in an O(2) background. Reactions of the heteronuclear oxide cations with methane in a fast-flow reactor were studied with a time-of-flight (TOF) mass spectrometer to detect the cluster distribution before and after the reactions. Hydrogen abstraction reactions were identified over stoichiometric cluster cations [(V(2)O(5))(n)(SiO(2))(m)](+) (n=1, m=1-4; n=2, m=1), and the estimated first-order rate constants for the reactions were close to that of the homonuclear oxide cluster V(4)O(10) (+) with methane. Density functional calculations were performed to study the structural, bonding, electronic, and reactivity properties of these stoichiometric oxide clusters. Terminal-oxygen-centered radicals (O(t)*) were found in all of the stable isomers. These O(t)* radicals are active sites of the clusters in reaction with CH(4). The O(t)* radicals in [V(2)O(5)(SiO(2))(1-4)](+) clusters are bonded with Si rather than V atoms. All the hydrogen abstraction reactions are favorable both thermodynamically and kinetically. This work reveals the unique properties of metal/nonmetal heteronuclear oxide clusters, and may provide new insights into CH(4) activation on silica-supported vanadium oxide catalysts.