Mass spectrometry of alkylbenzenes and related compounds. Part II. Gas phase ion chemistry of protonated alkylbenzenes (alkylbenzenium ions)

Kuck, Dietmar

doi:10.1002/mas.1280090602

Cited by 182 publications

(147 citation statements)

References 245 publications

Supporting

Mentioning

137

Contrasting

Unclassified

Order By: Relevance

“…1 The energetics argument cannot rationalize the relatively poorer exchange of the larger monalkylbenzenes. However, to exchange all aromatic hydrogens it is necessary that all ring positions be sampled, either by a hydrogen ring walk (35) in the protonated species or by interaction of the HDOR+ moiety in the intermediate complex with all different positions of the aromatic ring. Although it is known (35) that hydrogen randomization by the ring walk mechanism is relatively facile for protonated benzene, toluene, and the xylenes, it is possible that hydrogen randomization becomes less facile as the size of the alkyl group increases.…”

Section: Resultsmentioning

confidence: 99%

Reactive collisions in quadrupole cells. 6. H/D exchange reactions of protonated alkylbenzenes with D₂O, CH₃OD, and C₂H₅OD

Ni¹,

Harrison²

1995

Can. J. Chem.

View full text Add to dashboard Cite

The H/D exchange reactions occurring on collision of protonated alkylbenzenes with C2H5OD, CH3OD, and D2O at low collision energies in the quadrupole collision cell of a hybrid tandem mass spectrometer have been studied for 22 alkylbenzenes. The exchange reactions with D2O are much less efficient than the exchange reactions with C2H5OD or CH3OD; this difference is rationalized on energetics grounds. The H/D exchange of the protonated alkylbenzenes with C2H5OD or CH3OD leads, typically, to 40–70% deuterium incorporation in the protonated alkylbenzene and, for most cases, to significant ion signals corresponding to exchange of the added hydrogen and the aromatic hydrogens. Thus, the method is a feasible approach to counting the number of aromatic hydrogens in alkylbenzenes. The extent of exchange decreases with increasing size of the alkyl group in monoalkylbenzenes for reasons that are not readily understood. Keywords: protonated alkylbenzenes, H/D exchange, reactive collisions.

show abstract

Section: Resultsmentioning

confidence: 99%

Reactive collisions in quadrupole cells. 6. H/D exchange reactions of protonated alkylbenzenes with D₂O, CH₃OD, and C₂H₅OD

Ni¹,

Harrison²

1995

Can. J. Chem.

View full text Add to dashboard Cite

show abstract

“…In this case, losses of LiOD and LiCl were observed, but loss of LiOH was not ( Figure S2b). This implies that the hydrogen ring-walk [65] (it means that the deuteron migrated to the ortho-position will further exchange with the protons at the meta-positions and paraposition) following the 1,3-H shift does not take place.…”

Section: Investigation Of the Fragmentation Of The Lithiated N-phenylmentioning

confidence: 99%

Gas Phase Chemistry of Li⁺with Amides: the Observation of LiOH Loss in Mass Spectrometry

Guo

Zhou

Liu

et al. 2012

J. Am. Soc. Mass Spectrom.

View full text Add to dashboard Cite

of N-phenylbenzamide and N-phenylcinnamide. Loss of LiOH was essentially the sole fragmentation reaction observed for the former. For the latter, both losses of LiOH and H 2 O were discovered. The presence of electron-donating substituents of the phenyl ring of these compounds was found to facilitate elimination of LiOH, while that loss was retarded by electron-withdrawing substituents. Proposed fragment ion structures were supported by elemental compositions deduced from ultrahigh resolution Fourier transform ion cyclotron resonance tandem mass spectrometry (FTICR-MS/MS) m/z value determinations. Density functional theory-based (DFT) calculations were performed to evaluate potential mechanisms for these reactions.

show abstract

“…The rearrangement between benzyl cation and its isomer, tropylium ion, (Scheme 2) also receives considerable attraction and is still in debate [9][10][11][12][13]. Although tropylium is more stable than benzylium, theoretical calculations suggest that conversion of benzylium to tropylium must surmount a significant energy barrier which is about 280 kJ mol −1 [14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Gas-Phase Chemistry of Benzyl Cations in Dissociation ofN-Benzylammonium andN-Benzyliminium Ions Studied by Mass Spectrometry

Chai

Wang

Sun

et al. 2012

J. Am. Soc. Mass Spectrom.

View full text Add to dashboard Cite

In this study, the fragmentation reactions of various N-benzylammonium and N-benzyliminium ions were investigated by electrospray ionization mass spectrometry. In general, the dissociation of N-benzylated cations generates benzyl cations easily. Formation of ion/neutral complex intermediates consisting of the benzyl cations and the neutral fragments was observed. The intra-complex reactions included electrophilic aromatic substitution, hydride transfer, electron transfer, proton transfer, and nucleophilic aromatic substitution. These five types of reactions almost covered all the potential reactivities of benzyl cations in chemical reactions. Benzyl cations are well-known as Lewis acid and electrophile in reactions, but the present study showed that the gas-phase reactivities of some suitably ring-substituted benzyl cations were far richer. The 4-methylbenzyl cation was found to react as a Brønsted acid, benzyl cations bearing a strong electron-withdrawing group were found to react as electron acceptors, and parahalogen-substituted benzyl cations could react as substrates for nucleophilic attack at the phenyl ring. The reactions of benzyl cations were also related to the neutral counterparts. For example, in electron transfer reaction, the neutral counterpart should have low ionization energy and in nucleophilic aromatic substitution reaction, the neutral counterpart should be piperazine or analogues. This study provided a panoramic view of the reactions of benzyl cations with neutral N-containing species in the gas phase.

show abstract

Mass spectrometry of alkylbenzenes and related compounds. Part II. Gas phase ion chemistry of protonated alkylbenzenes (alkylbenzenium ions)

Cited by 182 publications

References 245 publications

Reactive collisions in quadrupole cells. 6. H/D exchange reactions of protonated alkylbenzenes with D₂O, CH₃OD, and C₂H₅OD

Reactive collisions in quadrupole cells. 6. H/D exchange reactions of protonated alkylbenzenes with D₂O, CH₃OD, and C₂H₅OD

Gas Phase Chemistry of Li⁺with Amides: the Observation of LiOH Loss in Mass Spectrometry

Gas-Phase Chemistry of Benzyl Cations in Dissociation ofN-Benzylammonium andN-Benzyliminium Ions Studied by Mass Spectrometry

Contact Info

Product

Resources

About

Mass spectrometry of alkylbenzenes and related compounds. Part II. Gas phase ion chemistry of protonated alkylbenzenes (alkylbenzenium ions)

Cited by 182 publications

References 245 publications

Reactive collisions in quadrupole cells. 6. H/D exchange reactions of protonated alkylbenzenes with D2O, CH3OD, and C2H5OD

Reactive collisions in quadrupole cells. 6. H/D exchange reactions of protonated alkylbenzenes with D2O, CH3OD, and C2H5OD

Gas Phase Chemistry of Li+with Amides: the Observation of LiOH Loss in Mass Spectrometry

Gas-Phase Chemistry of Benzyl Cations in Dissociation ofN-Benzylammonium andN-Benzyliminium Ions Studied by Mass Spectrometry

Contact Info

Product

Resources

About

Reactive collisions in quadrupole cells. 6. H/D exchange reactions of protonated alkylbenzenes with D₂O, CH₃OD, and C₂H₅OD

Reactive collisions in quadrupole cells. 6. H/D exchange reactions of protonated alkylbenzenes with D₂O, CH₃OD, and C₂H₅OD

Gas Phase Chemistry of Li⁺with Amides: the Observation of LiOH Loss in Mass Spectrometry