The formation of the anilinium ion from the ammonium ion in the ammonia chemical ionization of substituted benzenes

Stone, John A.; Splinter, Dena E.; McLaurin, JoAnne; Wojtyniak, Anastasia C. M.

doi:10.1002/oms.1210190805

Cited by 4 publications

(1 citation statement)

References 9 publications

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“…and neutral ammonia [19]. Later, Stone et al showed that also [NH 4 ] + can act as the reagent ion [20]. Ipso-substitution has also been shown to take place in clusters of aryl halides and ammonia after resonant multiphoton ionization [21][22][23][24][25][26].…”

Section: And [M + H]mentioning

confidence: 99%

Nucleophilic Aromatic Substitution Between Halogenated Benzene Dopants and Nucleophiles in Atmospheric Pressure Photoionization

Kauppila

Haack

Kroll

et al. 2015

J. Am. Soc. Mass Spectrom.

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Abstract. In a preceding work with dopant assisted-atmospheric pressure photoionization (DA-APPI), an abundant ion at [M + 77] + was observed in the spectra of pyridine and quinoline with chlorobenzene dopant. This contribution aims to reveal the identity and route of formation of this species, and to systematically investigate structurally related analytes and dopants. Compounds containing N-, O-, and S-lone pairs were investigated with APPI in the presence of fluoro-, chloro-, bromo-, and iodobenzene dopants. Computational calculations on a density functional theory (DFT) level were carried out to study the reaction mechanism for pyridine and the different halobenzenes. The experimental and computational results indicated that the [M + 77] + ion was formed by nucleophilic aromatic ipso-substitution between the halobenzene radical cation and nucleophilic analytes. The reaction was most efficient for N-heteroaromatic compounds, and it was weakened by sterical effects and enhanced by resonance stabilization. The reaction was most efficient with chloro-, bromo-, and iodobenzenes, whereas with fluorobenzene the reaction was scarcely observed. The calculated Gibbs free energies for the reaction between pyridine and the halobenzenes were shown to increase in the order I < Br < Cl < F. The reaction was found endergonic for fluorobenzene due to the strong C-F bonding, and exergonic for the other halobenzenes. For fluoro-and chlorobenzenes the reaction was shown to proceed through an intermediate state corresponding to [M + dopant] + , which was highly stable for fluorobenzene. For the bulkier bromine and iodine, this intermediate did not exist, but the halogens were shown to detach already during the approach by the nucleophile.

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Section: And [M + H]mentioning

confidence: 99%

Nucleophilic Aromatic Substitution Between Halogenated Benzene Dopants and Nucleophiles in Atmospheric Pressure Photoionization

Kauppila

Haack

Kroll

et al. 2015

J. Am. Soc. Mass Spectrom.

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Use of ion-molecule reactions for selected reaction monitoring in gas chromatographic/tandem mass spectrometric analyses in two model systems

Kinter

Bursey

1988

Biol. Mass Spectrom.

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The use of ion-molecule reactions with NH3 for selected reaction monitoring (SRM) in gas chromatographic/tandem mass spectrometric analysis is demonstrated for 2-methoxyethanol and chlorobenzene in methanol and urine. In the former, the reaction [CH3OC2H4]+ + NH3----[H2NC2H4]+ + CH3OH was followed; in the latter, the reaction [-C3H5Cl]+. + NH3----[C6H5NH3]+ + Cl.. Increased selectivity and an improvement in sensitivity by factors of up to five were observed when compared to conventional SRM analyses that used collisionally activated decompositions on NH3. SRM analyses with a triple quadrupole tandem mass spectrometer using ion-molecule reactions rather than collisionally activated decompositions have been found to be more sensitive and more selective in two model systems.

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Ammonia chemical ionization mass spectrometry

Westmore

Alauddin

1986

Mass Spectrometry Reviews

115

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The formation of the anilinium ion from the ammonium ion in the ammonia chemical ionization of substituted benzenes

Cited by 4 publications

References 9 publications

Nucleophilic Aromatic Substitution Between Halogenated Benzene Dopants and Nucleophiles in Atmospheric Pressure Photoionization

Nucleophilic Aromatic Substitution Between Halogenated Benzene Dopants and Nucleophiles in Atmospheric Pressure Photoionization

Use of ion-molecule reactions for selected reaction monitoring in gas chromatographic/tandem mass spectrometric analyses in two model systems

Ammonia chemical ionization mass spectrometry

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