Collisional activation and metastable ion characteristics. 53. Thirteen stable isomers of gaseous C8H9+ cations

Koeppel, Claus; Sande, C. C. Van De; Nibbering, N. M. M.; Nishishita, Takao; McLafferty, Fred W.

doi:10.1021/ja00451a006

Cited by 37 publications

(5 citation statements)

References 16 publications

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“…Such a situation has been met in a CA study of the structure of the (C,H9)+ ion generated by loss of the bromine atom from the molecular ion of 2-phenylethyl bromide (50). The ionic species was suspected (155) to have the phenonium ion structure (52) when generated at low ionizing energies, presumably via transition state 51 (Scheme 11). Evidence for this has been obtained from specific deuterium labeling of the methylene groups, which are eliminated with equal probability upon CA from the (M -Br)+ ions of 50, thus showing their expected equivalency to the ethylenebenzenium ion (52).…”

Section: C6h5mentioning

confidence: 99%

See 1 more Smart Citation

Gas‐phase chemistry of collisionally activated ions

Levsen¹,

Schwarz²

1983

Mass Spectrometry Reviews

293

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Section: C6h5mentioning

confidence: 99%

“…The homotropylium ion (2981, the ethylenebenzenium ion (521, and protonated benzocyclobutene (299) as well as the tricyclic ion 300 were also found to be stable. No evidence of stability, however, could be presented for the pphenylethyl cation (301) (155).…”

Section: -N+mentioning

confidence: 99%

Gas‐phase chemistry of collisionally activated ions

Levsen¹,

Schwarz²

1983

Mass Spectrometry Reviews

293

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“…In conclusion, proton transfer reactions on gaseous benzocyclobutene provide an access to the rich ion chemistry of C 8 H 9 + isomers 44,45 which will be further explored.…”

Section: Discussionmentioning

confidence: 99%

Gas-Phase Protonation of Benzocycloalkenes

Chiavarino

Crestoni

Fornarini

2004

Eur J Mass Spectrom (Chichester)

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The gas-phase basicity (GB) of four benzocycloalkenes (benzocyclobutene, indan, tetralin and benzocycloheptene) has been determined by Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry, allowing proton transfer equilibria to be established with reference bases of known GB. The values obtained are all very similar, 776.8-778.8 kJ mol-1 at 300 K, practically equal within experimental error and close to the GB of o-xylene. In this respect, any specific behavior which might be ascribed to the size of the fused ring is not manifested. H/D exchange reactions with CH 3 OD have been used to probe the structure of the protonated benzocycloalkenes. The positive-ion chemistry of protonated benzocyclobutene is characterized by its kinetic instability towards rearrangement into a more stable isomer(s). The isomerization is prompted either by an exothermic protonation process, for example using i-C 3 H 7 + as proton donor, or within an ion neutral complex with a polar molecule.

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“…10 According to collisional activation mass spectra no evidence for I ions of g10 -5 s lifetimes has been found. 11 A posterior collisional activation study has also shown that 1 does not interconvert with 2. 12 A more recent gas-phase study, however, reports a different behavior under high-pressure conditions where the phenonium ion is primarily obtained from the highly exothermic addition of the phenylium ion to ethylene but is rapidly converted to 2 (see Scheme 1).…”

Section: Introductionmentioning

confidence: 99%

“…Several phenonium ions including the unsubstituted phenonium ion have been reported to be present in the gas phase. [10][11][12][13][14][15][16] In contrast with the results obtained in superacid media, experimental studies in the gas phase have reported that the ionization of β-phenylethyl halides yielded 1 and 3 (see Scheme 1) but no 2 could be detected. 10 According to collisional activation mass spectra no evidence for I ions of g10 -5 s lifetimes has been found.…”

Section: Introductionmentioning

confidence: 99%

Rearrangements Involving the Phenonium Ion: A Theoretical Investigation

et al. 2001

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Rearrangements involving the phenonium ion were investigated by means of a B3LYP/6-311G(d,p) study in which the effect of solvent has been incorporated by using a PCM solvation model. A rationalization of the whole set of experimental facts reported both in the gas phase and in solution was possible thanks to the characterization of protonated benzocyclobutene as a minimum energy structure and, particularly, to the important preferential stabilization in solution of the TS for the isomerization of the phenonium ion to the alpha-methylbenzyl ion, which reduces the Gibbs energy barrier of 26.6 kcal/mol for this process in the gas phase to a more accessible one of 18.7 kcal/mol in solution.

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Collisional activation and metastable ion characteristics. 53. Thirteen stable isomers of gaseous C8H9+ cations

Cited by 37 publications

References 16 publications

Gas‐phase chemistry of collisionally activated ions

Gas‐phase chemistry of collisionally activated ions

Gas-Phase Protonation of Benzocycloalkenes

Rearrangements Involving the Phenonium Ion: A Theoretical Investigation

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