Photochemical Reaction Pathways of Carbon Tetrabromide in Solution Probed by Picosecond X-ray Diffraction.
We report a liquid-phase time-resolved X-ray diffraction study that resolves the molecular structures of the short-lived intermediates formed in the photodissociation of tetrabromomethane in methanol. Time-resolved X-ray diffraction can detect all chemical species simultaneously, and the diffraction...
| Publicado en: | Journal of the American Chemical Society Vol. 129; no. 44; pp. 13584 - 13592 |
|---|---|
| Autores principales: | , , , , |
| Formato: | Artículo |
| Publicado: |
American Chemical Society
11/7/2007
|
| Materias: | |
| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=hlh&AN=27483533&site=ehost-live header: @attributes: shortDbName: hlh uiTerm: 27483533 longDbName: Humanities International Complete uiTag: AN controlInfo: bkinfo: jinfo: jid: 00027863 ACS jtl: Journal of the American Chemical Society issn: 00027863 maglogo: N pubinfo: dt: 11/7/2007 vid: 129 iid: 44 pid: 997 pub: American Chemical Society artinfo: ui: 27483533 10.1021/ja073503e ppf: 13584 ppct: 8 formats: tig: atl: Photochemical Reaction Pathways of Carbon Tetrabromide in Solution Probed by Picosecond X-ray Diffraction. aug: au: Qingyu Kong Wulff, Michael Jae Hyuk Lee Bratos, Savo Ihee, Hyotcherl affil: European Synchrotron Radiation Facility, Grenoble Cedex 38043, BP 220, France National Creative Research Initiative Center for Time-Resolved Diffraction, Department of Chemistry and School of Molecular Science (BK2J), Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 305-701, Republic of Korea Laboratoire de Physique, Théorique des Liquides, Université Pierre et Marie Curie, Case Courrier 121, 4 Place Jussieu, Paris Cedex 75252, France su: Chemical research Bromides Carbon compounds Chemical reactions Solution (Chemistry) X-ray diffraction Photochemistry sug: subj: Chemical research Bromides Carbon compounds Chemical reactions Solution (Chemistry) X-ray diffraction Photochemistry ab: We report a liquid-phase time-resolved X-ray diffraction study that resolves the molecular structures of the short-lived intermediates formed in the photodissociation of tetrabromomethane in methanol. Time-resolved X-ray diffraction can detect all chemical species simultaneously, and the diffraction signal from each chemical species can be quantitatively calculated from molecular structures and compared with experimental data with high accuracy and precision. The photochemistry of carbon tetrahalides has long been explored to describe their reactions in the natural environment due to its relevance to ozone depletion. Excited with an ultraviolet optical pulse, the complicated photodissociation dynamics of CBr was followed in a wide temporal range from picoseconds up to microseconds and associated rate coefficients were determined by analyzing time-resolved diffraction patterns accumulated from 100 Ps X-ray pulses. The homolytic cleavage of one C-Br bond in the parent CBr molecule yields the CBr and Br radicals, which escape from the solvent cage and combine nongeminately to form CBr and Br, respectively. CBr eventually decays to give CBr and Br as final stable products. Our diffraction data at the current signal- to-noise ratio could not provide any evidence for the geminate recombination of the CBr and Br radicals to form the BrCBr-Br isomer or the solvated ion pair, implying that their formation is a minor channel compared with those observed clearly by time-resolved diffraction in this work. pubtype: Academic Journal doctype: Article src: R language: English refInfo: copyright: @attributes: flag: Y dt: @attributes: year: 2007 holdings: @attributes: islocal: N |
|---|