Structure and Chemistry of the Heteronuclear Oxo-Cluster [VPO₄]^•+: A Model System for the Gas-Phase Oxidation of Small Hydrocarbons

Abstract

The heteronuclear oxo-cluster [VPO4](•+) is generated via electrospray ionization and investigated with respect to both its electronic structure as well as its gas-phase reactivity toward small hydrocarbons, thus permitting a comparison to the well-known vanadium-oxide cation [V2O4](•+). As described in previous studies, the latter oxide exhibits no or just minor reactivity toward small hydrocarbons, such as CH4, C2H6, C3H8, n-C4H10, and C2H4, while substitution of one vanadium by a phosphorus atom yields the reactive [VPO4](•+) ion; the latter brings about oxidative dehydrogenation (ODH) of saturated hydrocarbons, e.g., propane and butane as well as oxygen-atom transfer (OAT) to unsaturated hydrocarbons, e.g. ethene, at thermal conditions. Further, the gas-phase structure of [VPO4](•+) is determined by IR photodissociation spectroscopy and compared to that of [V2O4](•+). DFT calculations help to elucidate the reaction mechanism. The results underline the crucial role of phosphorus in terms of C-H bond activation of hydrocarbons by mixed VPO clusters.

Cryogenic ion trap vibrational spectroscopy of hydrogen-bonded clusters relevant to atmospheric chemistry

“…These lasers often lack the photon fluences to effectively induce multiple photon absorption processes. The experiments described here were performed either at the FEL facility FELIX [133] or using the IR OPO/OPA table-top lasers in Berlin [102,136]. Table-top lasers are used for vibrational predissociation spectroscopy routinely in the region >2000 cm −1 , and more recently also in the 600-2000 cm −1 region.…”

Synthesis, Characterization, and Electrochemical Analyses of Vanadocene Tetrametaphosphate and Phosphinate Derivatives

“…As such, this process has been the subject of extensive mechanistic investigations over the decades, [5][6][7][8][9] and continues to be the subject of considerable interest today. [10][11][12][13][14] However, in spite of these extensive studies, no consensus mechanism yet exists as to the exact steps of this transformation.…”

Facile synthesis of highly ordered mesoporous chromium–alumina catalysts with improved catalytic activity and stability

“…[4][5][6] Transition metal catalysts are known for their redox properties and for their capacity to catalyze the oxidation of hydrocarbons. [7][8][9][10] In the last two decades, considerable efforts, applied as well as fundamental research have been spent on the activation and functionalization of hydrocarbons catalyzed by transition metal catalysts, including cyclohexane oxidation that represented a typical example of this kind of reactions. 6,[11][12][13][14] In addition, compared with common catalysts such as Beta-zeollites, 15 CNBF, 16 CNTs, 5 etc., supported transition metal oxide catalysts could remarkably promote the decomposition of H 2 O 2 and the formation of hydroxyl radicals OHÁ with much higher reactivity than that of oxygen to facilitate the oxidation of cyclohexane at a relatively lower temperature and increase the selectivity of the target products, which have been widely used for the selective oxidation of cyclohexane.…”