An energy-resolved study of the fragmentation of protonated polyfluoro- and polychloro-benzenes

Tkaczyk, Martin; Harrison, Alex G.

doi:10.1016/0168-1176(90)85072-a

Cited by 11 publications

(10 citation statements)

References 18 publications

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“…Similarly to IRMPD, both CID experiments of ringprotonated C 6 H 6 F + (1, 2) at low collision energies and unimolecular dissociation favor HF loss over H 2 elimination. 26,32,39 On the other hand, CID at high collision energies induces preferentially H 2 loss rather than HF loss. 27,31,40 Apparently, high excitation of 1 and 2 via a single excitation event leads to direct ejection of H 2 , which is fast on the time scale required for isomerization via the high barrier toward HF elimination (Figure 2).…”

Section: Resultsmentioning

confidence: 99%

“…Until recently, all experimental information about C 6 H 6 F + isolated in the gas phase came from the radiolytic approach , and mass spectrometric techniques, ,,,,,− including high-pressure mass spectrometry, proton-transfer equilibria measurements, metastable decay analysis, kinetic energy release measurements, and collision-induced dissociation (CID) experiments. The protonation sites of C 6 H 6 F + generated by either chemical ionization (CI) or electron ionization (EI) were found to strongly depend on the experimental ion source conditions, such as temperature, pressure, and the protonating agent and precursor used for the CI and EI processes, respectively.…”

Section: Introductionmentioning

confidence: 99%

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Protonation Sites of Isolated Fluorobenzene Revealed by IR Spectroscopy in the Fingerprint Range

et al. 2005

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Protonated fluorobenzene ions (C6H6F+) are produced by chemical ionization of C6H5F in the cell of a FT-ICR mass spectrometer using either CH5+ or C2H5+. The resulting protonation sites are probed by IR multiphoton dissociation (IRMPD) spectroscopy in the 600-1700 cm-1 fingerprint range employing the free electron laser at CLIO (Centre Laser Infrarouge Orsay). Comparison with quantum chemical calculations reveals that the IRMPD spectra are consistent with protonation in para and/or ortho position, which are the thermodynamically favored protonation sites. The lack of observation of protonation at the F substituent, when CH5+ is used as protonating agent, is attributed to the low-pressure conditions in the ICR cell where the ions are produced. Comparison of the C6H6F+ spectrum with IR spectra of C6H5F and C6H7+ reveals the effects of both protonation and H F substitution on the structural properties of these fundamental aromatic molecules.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Protonation Sites of Isolated Fluorobenzene Revealed by IR Spectroscopy in the Fingerprint Range

et al. 2005

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“…As for the gas phase, until recently all experimental information for isolated C 6 H 6 F þ was provided either from the radiolytic approach 64,65 or from mass spectrometry, 53,55,56,60,61,[66][67][68][69][70] including high-pressure mass spectrometry, proton transfer equilibria measurements, metastable decay (MD) analysis, kinetic energy release measurements, and collision-induced dissociation (CID) experiments. The protonation sites inferred for C 6 H 6 F þ , when produced by either chemical ionization (CI) or electron ionization (EI), depended strongly on the ion source conditions, including temperature, pressure, and the protonating agent and precursor employed for the CI and EI processes, respectively.…”

Section: Background Information For C 6 H 6 F Rmentioning

confidence: 99%

“…Similarly to IRMPD, both CID experiments of ring-protonated C 6 H 6 F þ (1, 2) at low collision energies and unimolecular dissociation favor HF over H 2 elimination. 55,61,68 On the other hand, CID at high collision energies induces preferentially H 2 loss rather than HF loss. 56,60,69 Hence, high excitation of 1 and 2 via a single excitation event leads to direct ejection of H 2 , which is fast on the timescale required for isomerization via the high barrier toward HF elimination (Fig.…”

Section: Irmpd Of C 6 H 6 F Rmentioning

confidence: 99%

IR spectroscopic strategies for the structural characterization of isolated and microsolvated arenium ions

Dopfer

2006

J of Physical Organic Chem

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This contribution summarizes recent experimental developments in coupling modern sensitive IR spectroscopic techniques with selective mass spectrometric methods, which have allowed for the first time for the unambiguous structural characterization of isolated and microsolvated protonated aromatic molecules in the gas phase. The two major experimental strategies involve (i) single-photon IR photodissociation (IRPD) spectroscopy in a tandem quadrupole mass spectrometer using novel optical parametric oscillator (OPO) laser systems in the 2500-4000 cm À1 range and (ii) IR multiphoton dissociation (IRMPD) spectroscopy in a Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer using high-intensity free electron lasers (FEL) in the 500-2500 cm À1 range. Both techniques offer complementary spectroscopic information, which is highlighted for the various isomers of protonated fluorobenzene, a simple prototype for protonated aromatic molecules. The analysis of the IR spectra provides unprecedented experimental insight into structure, energetics, and chemical reactivity of these fundamental reactive intermediates under isolated and controlled microsolvation conditions.

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“…The[137] /[136] ratio with (a) the temperature of the ionization chamber 40b) and (b) the bombarding electron energy 40c) for o-, m-, and p-toluic acid isobutyl esters.…”

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confidence: 99%

Studies of Fragmentation and Structure of Several Organic Ions by Using MIKE Spectrometry and Thermochemistry

Tajima

2003

J. Mass Spectrom. Soc. Jpn.

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It is summarized that the fragmentation and structure of several organic ions, including organosilicon and organofluorine ions, have been investigated by using ion kinetic energy (IKE) spectrometry, mass-analyzed ion kinetic energy (MIKE) spectrometry, D-labeling technique and thermochemistry. Further, several new methods, such as collision energy-dependent collision-induced dissociation (CID) spectra are described. ῒ ῍ ῐQῘῥQQQῖῌ ̮QQQῤ̰ῪQ῝̯QQ̰Q̱ ῥ̯Qῌ ̮̰ῧQQQQῥQQ΅ΰQ̯̮Ύ ̰ CID ῥQQ̮̰ῌ p-´ῼ ῼ ῳ ̮̰ῥ

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An energy-resolved study of the fragmentation of protonated polyfluoro- and polychloro-benzenes

Cited by 11 publications

References 18 publications

Protonation Sites of Isolated Fluorobenzene Revealed by IR Spectroscopy in the Fingerprint Range

Protonation Sites of Isolated Fluorobenzene Revealed by IR Spectroscopy in the Fingerprint Range

IR spectroscopic strategies for the structural characterization of isolated and microsolvated arenium ions

Studies of Fragmentation and Structure of Several Organic Ions by Using MIKE Spectrometry and Thermochemistry

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