Gas-phase reactions of the dichlorocarbene radical cation

Nelson, Eric D.; Tichy, Shane E.; Kenttämaa, Hilkka I.

doi:10.1039/a903936h

Cited by 12 publications

(9 citation statements)

References 31 publications

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“…The occurrence of direct chlorine atom abstraction is, however, unlikely considering the conclusions reached recently for the reaction of ionized halocarbenes with haloalkanes 17. It was shown that both halide ion and halogen atom abstractions proceed via a common intermediate resulting from electrophilic attack to form a dialkylhalonium ion 17. The intermediate fragments either homolytically or heterolytically to produce net halogen atom or halide ion transfer products, respectively, as shown in Scheme .…”

Section: Resultsmentioning

confidence: 98%

“…The former can be viewed as the product of a Cl atom abstraction and, thus, be ascribed to the radical character of ionized carbenes. The occurrence of direct chlorine atom abstraction is, however, unlikely considering the conclusions reached recently for the reaction of ionized halocarbenes with haloalkanes 17. It was shown that both halide ion and halogen atom abstractions proceed via a common intermediate resulting from electrophilic attack to form a dialkylhalonium ion 17.…”

Section: Resultsmentioning

confidence: 99%

“…Since the reactivity of ionized halogen‐containing carbenes is largely unexplored,17 it was of particular interest to study the reactions of the ionized carbenes CX 2 + (X = Cl and/or F) with the neutrals 1,1,1 and 1,1,2 . All of these ions react with either 1,1,1 or 1,1,2 to give two products, the trivalent carbenium ion CClX 2 + and [M − Cl] + .…”

Section: Resultsmentioning

confidence: 99%

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Products, rate constants and mechanisms of gas‐phase reactions of CX₃⁺, CX₂⁺, CX⁺ (X = F and/or Cl) and Cl⁺ with 1,1,1‐ and 1,1,2‐trichlorotrifluoroethane

Marotta

Paradisi

2001

J. Mass Spectrom.

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The gas-phase ion chemistry of 1,1,1- and 1,1,2-trichlorotrifluoroethane was investigated with an ion trap mass spectrometer. Following electron ionization both compounds (M) fragment to [M - Cl](+), CX(3)(+), CX(2)(+), CX(+) (X = F and/or Cl) and Cl(+). The reactivity of each of these fragments towards their neutral precursors was studied to obtain product and kinetic data. Whereas [M - Cl](+), CCl(3)(+) and CCl(2)F(+) cations are unreactive under the experimental conditions used, all other species react via halide abstraction to give [M - Cl](+) and, to a far lesser extent, [M - F](+). In addition, CX(2)(+) ions form CClX(2)(+) in a process which formally amounts to chlorine atom abstraction, but more likely involves chloride ion abstraction followed by charge transfer. CX(+) ions also form minor amounts of CX(3)(+) product ions, possibly via chloride abstraction followed by or concerted with dihalocarbene elimination from the (incipient) [M - Cl](+) ion. Trivalent carbenium ions are less reactive than divalent species, which in turn are less reactive than the monovalent ions (reaction efficiencies are given in parentheses): CF(3)(+)(0.70) < CF(2)(+)(0.78) < CF(+)(0.96). More interestingly, within each family of ions reactivity increases with the number of fluorine substituents (e.g. CF(2)(+) > CFCl(+) > CCl(2)(+) and CF(+) > CCl(+)), i.e. reactivity increases with the ion thermochemical stability, as measured by available standard free enthalpies of formation. Evaluation of the energetics involved shows that reactions are largely driven by the stability of the neutrals more than of the ions. Finally, the products observed in the reaction of Cl(+) are attributed to ionization of the neutral via charge transfer and fragmentation.

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Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Products, rate constants and mechanisms of gas‐phase reactions of CX₃⁺, CX₂⁺, CX⁺ (X = F and/or Cl) and Cl⁺ with 1,1,1‐ and 1,1,2‐trichlorotrifluoroethane

Marotta

Paradisi

2001

J. Mass Spectrom.

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“…3). Analogous reactions were observed with haloalkanes12 and chlorofluorocarbons,11 and rationalized on the basis of the mechanism indicated in Scheme which comprises both halide ion and halogen atom abstraction steps proceeding via a common intermediate 12. The intermediate, a dialkylhalonium ion radical, fragments either homolytically or heterolytically to produce net halogen atom or halide ion transfer products, respectively, as shown in Scheme .…”

Section: Resultsmentioning

confidence: 72%

Gas‐phase positive ion chemistry of 1‐bromo‐1‐chloro‐2,2,2‐trifluoroethane (halothane) upon electron ionization within an ion trap mass spectrometer

Marotta

Scorrano

Paradisi

2005

Rapid Comm Mass Spectrometry

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The positive ion chemistry occurring within an ion trap mass spectrometer upon electron ionization of 1-bromo-1-chloro-2,2,2-trifluoroethane, the important anaesthetic halothane, has been mapped by means of collision-induced decomposition and ion/molecule self-reaction experiments. Ionized halothane (M+*) reacts with neutral halothane to form the ionized olefin [ClBrC=CF2]+*. via HF elimination. Among the ionic fragments, [M-Br]+ and [M-F]+ react with halothane via chloride abstraction while [M-Cl]+ is unreactive under the same experimental conditions. Substituted methyl cations CHFX+ and CF2X+ (X = F, Cl, Br) undergo halide transfer processes, their reactivity being highest for X = F. Ionized carbenes CXY+ (X,Y = F,F; H,Br; H,Cl; H,F) react with halothane to form CClXY+ and CBrXY+, whereas CF+ inserts into the C-Cl bond to form CF3+ and CClF2+. Finally, Br+ and Cl+ react with halothane by charge transfer. Collision-induced dissociation experiments disclosed interesting rearrangements involved in the dissociations of +CHX-CF3 ions (X = Br, Cl), which undergo fluorine migration and elimination of CF2, as already observed for +CCl2-CF3 in a previous investigation.

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“…Several recent articles deal with the reactions of ionized carbenes with neutral molecules [31][32][33]. More particularly, it has been recently shown that ionized carbenes, such as HO-C-OH •+ and HO-C-NH 2…”

Section: H • Abstraction From Methane By An Ionized Carbenementioning

confidence: 99%

Hydrogen radical abstraction by small ionized molecules, distonic ions and ionized carbenes in the gas phase

Nedev

Rest²,

Mourgues³

et al. 2004

International Journal of Mass Spectrometry

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Gas-phase reactions of the dichlorocarbene radical cation

Cited by 12 publications

References 31 publications

Products, rate constants and mechanisms of gas‐phase reactions of CX₃⁺, CX₂⁺, CX⁺ (X = F and/or Cl) and Cl⁺ with 1,1,1‐ and 1,1,2‐trichlorotrifluoroethane

Products, rate constants and mechanisms of gas‐phase reactions of CX₃⁺, CX₂⁺, CX⁺ (X = F and/or Cl) and Cl⁺ with 1,1,1‐ and 1,1,2‐trichlorotrifluoroethane

Gas‐phase positive ion chemistry of 1‐bromo‐1‐chloro‐2,2,2‐trifluoroethane (halothane) upon electron ionization within an ion trap mass spectrometer

Hydrogen radical abstraction by small ionized molecules, distonic ions and ionized carbenes in the gas phase

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Gas-phase reactions of the dichlorocarbene radical cation

Cited by 12 publications

References 31 publications

Products, rate constants and mechanisms of gas‐phase reactions of CX3+, CX2+, CX+ (X = F and/or Cl) and Cl+ with 1,1,1‐ and 1,1,2‐trichlorotrifluoroethane

Products, rate constants and mechanisms of gas‐phase reactions of CX3+, CX2+, CX+ (X = F and/or Cl) and Cl+ with 1,1,1‐ and 1,1,2‐trichlorotrifluoroethane

Gas‐phase positive ion chemistry of 1‐bromo‐1‐chloro‐2,2,2‐trifluoroethane (halothane) upon electron ionization within an ion trap mass spectrometer

Hydrogen radical abstraction by small ionized molecules, distonic ions and ionized carbenes in the gas phase

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Products, rate constants and mechanisms of gas‐phase reactions of CX₃⁺, CX₂⁺, CX⁺ (X = F and/or Cl) and Cl⁺ with 1,1,1‐ and 1,1,2‐trichlorotrifluoroethane

Products, rate constants and mechanisms of gas‐phase reactions of CX₃⁺, CX₂⁺, CX⁺ (X = F and/or Cl) and Cl⁺ with 1,1,1‐ and 1,1,2‐trichlorotrifluoroethane