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Titolo:
Unimolecular chemistry of (CH2)-C-center dot-O-C-center dot=O (methylenecarboxyldiradical) and HO-CH=C=O (hydroxyketene) and of the corresponding radical cations and anions in the gas phase
Autore:
Polce, MJ; Song, W; Cerda, BA; Wesdemiotis, C;
Indirizzi:
Univ Akron, Dept Chem, Akron, OH 44325 USA Univ Akron Akron OH USA 44325Univ Akron, Dept Chem, Akron, OH 44325 USA
Titolo Testata:
EUROPEAN JOURNAL OF MASS SPECTROMETRY
fascicolo: 2, volume: 6, anno: 2000,
pagine: 121 - 130
SICI:
1469-0667(2000)6:2<121:UCO(DD>2.0.ZU;2-C
Fonte:
ISI
Lingua:
ENG
Soggetto:
REIONIZATION MASS-SPECTROMETRY; NEUTRALIZATION-REIONIZATION; INTERNAL ENERGY; IONS; GENERATION; FRAGMENTATION; MOLECULES; DECOMPOSITION; PROBE; NRMS;
Keywords:
distonic radical ions; diradicals; ketenes; neutralization-reionization; charge reversal;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
35
Recensione:
Indirizzi per estratti:
Indirizzo: Wesdemiotis, C Univ Akron, Dept Chem, Akron, OH 44325 USA Univ Akron Akron OH USA 44325 pt Chem, Akron, OH 44325 USA
Citazione:
M.J. Polce et al., "Unimolecular chemistry of (CH2)-C-center dot-O-C-center dot=O (methylenecarboxyldiradical) and HO-CH=C=O (hydroxyketene) and of the corresponding radical cations and anions in the gas phase", EUR J MASS, 6(2), 2000, pp. 121-130

Abstract

The C2H2O2+ isomers (CH2)-C-.-O-C+=O (1(+.), methylenecarboxyl radical cation) and HO-CH=CCOO+. (2(+.), hydroxyketene radical cation) are produced inthe gas phase and their spontaneous and collision-induced decompositions are compared to those of the known glyoxal radical cation, O=CH-CH=O+. (3(+.)), At threshold, all three ions yield CH2=O+. + CO via unique pathways. 1(.) undergoes direct CO rupture with substantial reverse-activation energy,2(+.), after H-rearrangement to O-.-CH2-C+=O, loses CO without appreciablereverse-activation energy, and 3(+.) eliminates CO via the ion-dipole complex O+.=CH2. . . CO. The fragmentations of collisionally-activated 1(+.)-3(.) differ substantially, consistent with these ions being distinct C2H2O2+. radical cations, Charge reversal of 1(+.)-3(+.) shows that 1(+.) and 2(+.) are viable radical anions, The stabilities and reactivities of the corresponding neutral species are determined by neutralization of 1(+.)-3(+.) followed by reionization to either cations (+NR+) or anions (+NR+). Diradical 1 is found to be weakly bound by kinetic barriers and dissociates largely in the microsecond time scale to CH2 + CO2 and to CH2=O + CO. In contrast, ketene 2 mainly survives intact within the same time window, decomposing only to a small extent to H-. + O-.-CH=C=O. The extensive fragmentation observed upon +NR+ of 3(+.) is shown to occur in the reionization step and primarily reflects the low decomposition threshold of 3(+.).

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Documento generato il 10/07/20 alle ore 09:42:05