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Titolo:
Ion chemistry of anti-o,o '-dibenzene
Autore:
Schroeter, K; Schroder, D; Schwarz, H; Reddy, GD; Wiest, O; Carra, C; Bally, T;
Indirizzi:
Tech Univ Berlin, Inst Organ Chem, D-10623 Berlin, Germany Tech Univ Berlin Berlin Germany D-10623 an Chem, D-10623 Berlin, Germany Univ Notre Dame, Dept Chem & Biochem, Notre Dame, IN 46556 USA Univ Notre Dame Notre Dame IN USA 46556 Biochem, Notre Dame, IN 46556 USA Univ Fribourg, Inst Chim Phys, CH-1700 Fribourg, Switzerland Univ Fribourg Fribourg Switzerland CH-1700 CH-1700 Fribourg, Switzerland
Titolo Testata:
CHEMISTRY-A EUROPEAN JOURNAL
fascicolo: 23, volume: 6, anno: 2000,
pagine: 4422 - 4430
SICI:
0947-6539(200012)6:23<4422:ICOA'>2.0.ZU;2-J
Fonte:
ISI
Lingua:
ENG
Soggetto:
AB-INITIO CALCULATIONS; BENZENE RADICAL-CATION; TANDEM MASS-SPECTROMETRY; THROUGH-BOND INTERACTION; DIELS-ALDER REACTIONS; GAS-PHASE; ELECTRON-TRANSFER; FRAGMENT IONS; METAL-IONS; ISOMERIZATION;
Keywords:
dibenzene; cycloreversions; gas-phase chemistry; mass spectrometry; transition metals;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
67
Recensione:
Indirizzi per estratti:
Indirizzo: Schwarz, H Tech Univ Berlin, Inst Organ Chem, Str 17 June 135, D-10623 Berlin, Germany Tech Univ Berlin Str 17 June 135 Berlin Germany D-10623 ermany
Citazione:
K. Schroeter et al., "Ion chemistry of anti-o,o '-dibenzene", CHEM-EUR J, 6(23), 2000, pp. 4422-4430

Abstract

The ion chemistry of anti-o,o'-dibenzene (1) was examined in the gaseous and the condensed phase. From a series of comparative ion cyclotron resonance (ICR) mass spectrometry experiments which involved the interaction of Cuwith 1, benzene, or mixtures of both, it was demonstrated that 1 can be brought into the gas phase as an intact molecule under the experimental conditions employed. The molecular ions, formally 1(.+) and 1(.-), were investigated with a four-sector mass spectrometer in metastable-ion decay, collisional activation, charge reversal, and neutralization-reionization experiments. Surprisingly the expected retrocyclization to yield two benzene molecules was not dominant for the long-lived molecular ions; however, other fragmentations, such as methyl and hydrogen losses, prevailed. In contrast, matrix ionization of 1 in freon (77 K) by gamma -radiation or in argon (12 K) byX-irradiation leads to quantitative retrocyclization to the cationic dimerof benzene, 2(.+). Theoretical modeling of the potential-energy surface for the retrocyclization shows that only a small, if any, activation barrier is to be expected for this process. In another series of experiments, metalcomplexes of 1 were investigated. 1/Cr+ was formed in the ion source and examined by metastable ion decay and collisional activation experiments, which revealed predominant losses of neutral benzene. Nevertheless, comparisonwith the bis-ligated [(C6H6)(2)Cr](+) complex provided evidence for the existence of an intact 1/Cr+ under these experimental conditions. No evidencefor the existence of 1/Fe+ was obtained, which suggests that iron mediatesthe rapid retrocyclization of 1/Fe+ into the bis-ligated benzene complex [(C6H6)(2)Fe](+).

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Documento generato il 04/12/20 alle ore 15:26:57