Ab initio R1 mechanism of photostimulated oxygen isotope exchange reaction on a defect TiO2 surface: The case of terminal oxygen atom exchange

Carbon-Atom Exchange between [MC2]+ (M = Os and Ir) and Methane: on the Thermodynamic and Dynamic Aspects

“…Gas-phase studies of isotope exchange reactions in clusters of finite atomic number may be an effective way to reveal isotope exchange mechanisms and to resolve structure−performance relationships at a molecular level. 8,9 In contrast to the abundant studies of isotope exchange reactions in the condensed phase, 10−17 reports on gas-phase isotope exchange reactions are scarce, focusing mainly on H/D, 18−20 12 C/ 13 C, 21−24 14 N/ 15 N, 25 and 16 O/ 18 O 26−29 exchange reactions. For methane, a chemical feedstock that can be converted into high-value chemicals, 30,31 the study of its activation mechanism, especially the isotope exchange reaction mechanism, may be one of the thrusts for the development of stable isotopic tracer technique 32−36 and olefin metathesis.…”

“…On the other hand, stable isotope (deuterium and carbon-13) labeling is commonly used as internal standards for efficient analysis, such as liquid chromatograph mass spectrometer or magnetic resonance imaging techniques. , The H/D exchange and 12 C/ 13 C exchange reactions are commonly used for the preparation of internal standards in the condensed phase. − Furthermore, these exchange reactions can also be used to investigate the reaction mechanism in the gas phase, where idealized conditions can effectively reduce the heterogeneity of the active center morphology and the complexity of the chemical environment in the condensed phase. Gas-phase studies of isotope exchange reactions in clusters of finite atomic number may be an effective way to reveal isotope exchange mechanisms and to resolve structure–performance relationships at a molecular level. , In contrast to the abundant studies of isotope exchange reactions in the condensed phase, − reports on gas-phase isotope exchange reactions are scarce, focusing mainly on H/D, − 12 C/ 13 C, − 14 N/ 15 N, and 16 O/ 18 O − exchange reactions. For methane, a chemical feedstock that can be converted into high-value chemicals, , the study of its activation mechanism, especially the isotope exchange reaction mechanism, may be one of the thrusts for the development of stable isotopic tracer technique − and olefin metathesis. − …”

Ab Initio Insight into Mechanisms of Ozone Interaction with a Surface of Dehydrated Nanocrystalline TiO2

“…Dehydrated nanocrystalline TiO 2 is represented by the nanocluster Ti 8 O 16 , which was successfully used to model chemical reactions as well as adsorption phenomena on the oxide’s surface (NO reduction in the presence of CO, atomic hydrogen activation of TiO 2 nanoclusters, adsorption of O 2 and H 2 O, interaction of H 2 with photoexcited TiO 2 , and O 2 isotope exchange on TiO 2 ). It is worth noting that other models of nanocrystalline TiO 2 exist as well. , Although they seem to be more realistic than Ti 8 O 16 , their use for the modeling of TiO 2 surface phenomena would require significantly bigger computational effort.…”

“…Our choice of DFT is based on reliable results it usually provides at a rather moderate computational expense. Dehydrated nanocrystalline TiO 2 is represented by the nanocluster Ti 8 O 16 , which was successfully used to model chemical reactions as well as adsorption phenomena on the oxide's surface (NO reduction in the presence of CO, 18 atomic hydrogen activation of TiO 2 nanoclusters, 19 adsorption of O 2 20 and H 2 O, 21 interaction of H 2 with photoexcited TiO 2 , 22 and O 2 isotope exchange on TiO 2 23 ). It is worth noting that other models of nanocrystalline TiO 2 exist as well.…”