Ethene Insertion into Vanadium Hydride Intermediates Formed via Vanadium Atom Reaction with Water or Ethene: A Matrix Isolation Infrared Spectroscopic Study
| Autor: | J. Mark Parnis, Matthew G. K. Thompson |
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| Rok vydání: | 2008 |
| Předmět: | |
| Zdroj: | Inorganic Chemistry. 47:4045-4053 |
| ISSN: | 1520-510X 0020-1669 |
| DOI: | 10.1021/ic701653v |
| Popis: | The reaction of V atoms with H 2 O and various concentrations of C 2 D 4 in argon has been investigated by matrix isolation infrared (IR) spectroscopy. Both C 2 D 6 and CD 2 H-CD 2 H are observed as the major products of a set of parallel processes involving hydrogenation of ethene where the formal source of hydrogen is either C 2 D 4 or H 2 O. Portions of the IR spectrum of CD 2 H-CD 2 H isolated in an argon matrix are observed for the first time. For experiments involving low concentrations of C 2 D 4 , irradiation of the matrix with light of wavelengths >455 nm results in VH 2 formation, with limited observation of ethene hydrogenation. The source of H 2 is believed to be due to photoelimination of molecular hydrogen from HO-V-H species, during matrix deposition, with OV as an additional product. Recombination of OV with available H 2 in the matrix is proposed as the source of OVH 2 under low ethene conditions. No evidence for VD 2 formation is observed under our conditions. At higher C 2 D 4 concentrations, VH 2 formation is suppressed, while products of ethene hydrogenation are maximized. A second process competing with H 2 elimination in which HO-V-H reacts with C 2 D 4 is proposed. Parallel reaction schemes involving V atom insertion into the O-H bonds of water or the photoinduced insertion of V atoms into the C-D bonds of C 2 D 4 are proposed to account for the observed hydrogenation products. In each mechanism, insertion of C 2 D 4 into the V-H or V-D bonds of transient intermediates is followed by photoinduced elimination of the associated ethane isotopomer. |
| Databáze: | OpenAIRE |
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