Experimental and Theoretical Study of the Reactions between Neutral Vanadium Oxide Clusters and Ethane, Ethylene, and Acetylene

Abstract

Reactions of neutral vanadium oxide clusters with small hydrocarbons, namely C2H6, C2H4, and C2H2, are investigated by experiment and density functional theory (DFT) calculations. Single photon ionization through extreme ultraviolet (EUV, 46.9 nm, 26.5 eV) and vacuum ultraviolet (VUV, 118 nm, 10.5 eV) lasers is used to detect neutral cluster distributions and reaction products. The most stable vanadium oxide clusters VO2, V2O5, V3O7, V4O10, etc. tend to associate with C2H4 generating products V(m)O(n)C2H4. Oxygen-rich clusters VO3(V2O5)(n=0,1,2...), (e.g., VO3, V3O8, and V5O13) react with C2H4 molecules to cause a cleavage of the C=C bond of C2H4 to produce (V2O5)(n)VO2CH2 clusters. For the reactions of vanadium oxide clusters (V(m)O(n)) with C2H2 molecules, V(m)O(n)C2H2 are assigned as the major products of the association reactions. Additionally, a dehydration reaction for VO3 + C2H2 to produce VO2C2 is also identified. C2H6 molecules are quite stable toward reaction with neutral vanadium oxide clusters. Density functional theory calculations are employed to investigate association reactions for V2O5 + C2H(x). The observed relative reactivity of C2 hydrocarbons toward neutral vanadium oxide clusters is well interpreted by using the DFT calculated binding energies. DFT calculations of the pathways for VO3+C2H4 and VO3+C2H2 reaction systems indicate that the reactions VO3+C2H4 --> VO2CH2 + H2CO and VO3+C2H2 --> VO2C2 + H2O are thermodynamically favorable and overall barrierless at room temperature, in good agreement with the experimental observations.

Catalytic Redox Reactions in the CO/N2O System Mediated by the Bimetallic Oxide‐Cluster Couple AlVO3+/AlVO4+

“…[19] The DFT calculations have been carried out using the Gaussian 09 program [20] employing the hybrid B3LYP exchange-correlation functional [21] with the unrestricted Kohn-Sham solution, [22] and TZVP basis sets. [23] The unrestricted B3LYP/TZVP level of theory proved reliable in previous studies of cationic, [24] anionic, [25] and neutral [10] AlVO 5 À , [27] V 2 SiO 8 À , [28] V 2 SiO 7 + , [11d] and V 3 PO 10 +[11a,c] and their gas-phase reactions with small alkanes. For the optimization of transition structures (TS), we employed either the Berny algorithm [29] or the synchronous transitguided quasi-Newton (STQN) method.…”

“…[9] In addition, the experimental observation and theoretical investigation of a neutral VO 3 radical bearing a V-O t C center have been reported by Bernstein and co-workers. [10] More recently, the groups of Schwarz and He described the efficient, thermal activation of methane by various stoichiometric binary oxide clusters containing M-O t C centers; [11] one interesting example concerns the thermal activation of methane by AlVO 4 + as proposed by Wang et al [11b] Surprisingly, the M-O t C center of AlVO 4 + is located on the maingroup metal Al but not on the transition-metal V. The thermodynamic and kinetic driving force of methane activation is indeed related to the properties of the Al-O t C moiety.…”

Room‐Temperature CH Bond Activation of Methane by Bare [P4O10].+

“…[10] For the latter system, aluminum oxide cluster cations that have an odd number of aluminum atoms and lack an oxygen-centered radical do not react with methane. [10,11] Further studies on the role of oxygen-centered radicals in chemical reactions showed that other substrates, such as ethylene or acetylene, can also be activated by different radical transition-metal oxide clusters, such as neutral VO 3 C. [12] Room-temperature hydrogen-atom abstraction from methane by a metal-free radical cation oxide was reported recently by de Petris et al [13] In this elegant experimental and computational study, it was demonstrated that [SO 2 ]C + brings about efficient activation of methane [Eq. (2)] with a rate…”

Aktivierung der C‐H‐Bindung von Methan bei Raumtemperatur durch nacktes [P4O10].+

“…B. durch neutrales VO 3 , aktiviert werden können. [12] Kürzlich berichteten de Petris et al über die Aktivierung von Methan bei Raumtemperatur durch Abstraktion eines Wasserstoffatoms, wobei erstmals ein metallfreies radikalisches Oxidkation eingesetzt wurde. [13] Durch eine elegante Kombination von experimentellen und theoretischen Untersuchungen konnten sie zeigen, dass [SO 2 ]C + eine effektive Aktivierung von Methan ermöglicht [Gl.…”