Gas-phase Acidities of 2-Aryl-2-chloro-1,1,1-trifluoroethanes and Related Compounds. Experimental and Computational Studies

Masaaki Mishima, José Luis M. Abboud, Mizue Fujio, Masahiko Suenaga, Heinz F. Koch, Judith G. Koch

研究成果: ジャーナルへの寄稿記事

3 引用 (Scopus)

抄録

The gas-phase acidities (GA) of 2-aryl-2-chloro-1,1,1-trifluoroethanes (1a), 2-aryl-2-fluoro-1,1,1-trifluoroethanes (2a), and related compounds, XC6H4CH(Z)R where Z = Cl (1) or F (2) and R = C2F5 (b), t-C4F9 (c), C(CF3)2C2F5 (d), C(CF3)2Me (e), Me (f), H (g), were investigated experimentally and computationally. On the basis of an excellent linear correlation (R2 > 0.99) of acidities of 1c, 1d, 1e, 1f and 2c, 2d, 2e, 2f where there is no fluorine atom at β-position to the deprotonation site with the corrected number of fluorine atoms contained in the fluorinated alkyl group, the extent of β-fluorine negative hyperconjugation of the CF3 and C2F5 groups (ΔGo β-F) was evaluated. The GAel values given by subtraction ΔGo β-F from the apparent GA value were considered to represent the electronic effect of the substituent X. The substituent effects on the GAel values and GA values for 1c, 1d, 1e, 1f and 2c, 2d, 2e, 2f were successfully analyzed in terms of the Yukawa–Tsuno equation. The variation of resonance demand parameter r with the R group observed for various XC6H4CH(Z)R was linearly related to the GA (GAel) value of the respective phenyl-substituted fluorinated alkanes. On the other hand, the corresponding correlation for the ρ values provided three lines for ArCH(Cl)R, ArCH(F)R and ArCH2R, respectively. These results supported our previous conclusion that the r and ρ values are governed by the thermodynamic stability of the parent ion (ring substituent = H). Other factors arising from an atom bonded to the acidic center also influence the ρ value.

元の言語英語
ページ(範囲)523-531
ページ数9
ジャーナルJournal of Physical Organic Chemistry
29
発行部数10
DOI
出版物ステータス出版済み - 10 1 2016

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Acidity
acidity
Gases
Fluorine
vapor phases
fluorine
Atoms
atoms
Deprotonation
Alkanes
subtraction
alkanes
Thermodynamic stability
1,1,1-trifluoro-2-chloroethane
Ions
thermodynamics
rings
electronics
ions

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Organic Chemistry

これを引用

Gas-phase Acidities of 2-Aryl-2-chloro-1,1,1-trifluoroethanes and Related Compounds. Experimental and Computational Studies. / Mishima, Masaaki; Abboud, José Luis M.; Fujio, Mizue; Suenaga, Masahiko; Koch, Heinz F.; Koch, Judith G.

:: Journal of Physical Organic Chemistry, 巻 29, 番号 10, 01.10.2016, p. 523-531.

研究成果: ジャーナルへの寄稿記事

Mishima, Masaaki ; Abboud, José Luis M. ; Fujio, Mizue ; Suenaga, Masahiko ; Koch, Heinz F. ; Koch, Judith G. / Gas-phase Acidities of 2-Aryl-2-chloro-1,1,1-trifluoroethanes and Related Compounds. Experimental and Computational Studies. :: Journal of Physical Organic Chemistry. 2016 ; 巻 29, 番号 10. pp. 523-531.
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title = "Gas-phase Acidities of 2-Aryl-2-chloro-1,1,1-trifluoroethanes and Related Compounds. Experimental and Computational Studies",
abstract = "The gas-phase acidities (GA) of 2-aryl-2-chloro-1,1,1-trifluoroethanes (1a), 2-aryl-2-fluoro-1,1,1-trifluoroethanes (2a), and related compounds, XC6H4CH(Z)R where Z = Cl (1) or F (2) and R = C2F5 (b), t-C4F9 (c), C(CF3)2C2F5 (d), C(CF3)2Me (e), Me (f), H (g), were investigated experimentally and computationally. On the basis of an excellent linear correlation (R2 > 0.99) of acidities of 1c, 1d, 1e, 1f and 2c, 2d, 2e, 2f where there is no fluorine atom at β-position to the deprotonation site with the corrected number of fluorine atoms contained in the fluorinated alkyl group, the extent of β-fluorine negative hyperconjugation of the CF3 and C2F5 groups (ΔGo β-F) was evaluated. The GAel values given by subtraction ΔGo β-F from the apparent GA value were considered to represent the electronic effect of the substituent X. The substituent effects on the GAel values and GA values for 1c, 1d, 1e, 1f and 2c, 2d, 2e, 2f were successfully analyzed in terms of the Yukawa–Tsuno equation. The variation of resonance demand parameter r− with the R group observed for various XC6H4CH(Z)R was linearly related to the GA (GAel) value of the respective phenyl-substituted fluorinated alkanes. On the other hand, the corresponding correlation for the ρ values provided three lines for ArCH(Cl)R, ArCH(F)R and ArCH2R, respectively. These results supported our previous conclusion that the r− and ρ values are governed by the thermodynamic stability of the parent ion (ring substituent = H). Other factors arising from an atom bonded to the acidic center also influence the ρ value.",
author = "Masaaki Mishima and Abboud, {Jos{\'e} Luis M.} and Mizue Fujio and Masahiko Suenaga and Koch, {Heinz F.} and Koch, {Judith G.}",
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T1 - Gas-phase Acidities of 2-Aryl-2-chloro-1,1,1-trifluoroethanes and Related Compounds. Experimental and Computational Studies

AU - Mishima, Masaaki

AU - Abboud, José Luis M.

AU - Fujio, Mizue

AU - Suenaga, Masahiko

AU - Koch, Heinz F.

AU - Koch, Judith G.

PY - 2016/10/1

Y1 - 2016/10/1

N2 - The gas-phase acidities (GA) of 2-aryl-2-chloro-1,1,1-trifluoroethanes (1a), 2-aryl-2-fluoro-1,1,1-trifluoroethanes (2a), and related compounds, XC6H4CH(Z)R where Z = Cl (1) or F (2) and R = C2F5 (b), t-C4F9 (c), C(CF3)2C2F5 (d), C(CF3)2Me (e), Me (f), H (g), were investigated experimentally and computationally. On the basis of an excellent linear correlation (R2 > 0.99) of acidities of 1c, 1d, 1e, 1f and 2c, 2d, 2e, 2f where there is no fluorine atom at β-position to the deprotonation site with the corrected number of fluorine atoms contained in the fluorinated alkyl group, the extent of β-fluorine negative hyperconjugation of the CF3 and C2F5 groups (ΔGo β-F) was evaluated. The GAel values given by subtraction ΔGo β-F from the apparent GA value were considered to represent the electronic effect of the substituent X. The substituent effects on the GAel values and GA values for 1c, 1d, 1e, 1f and 2c, 2d, 2e, 2f were successfully analyzed in terms of the Yukawa–Tsuno equation. The variation of resonance demand parameter r− with the R group observed for various XC6H4CH(Z)R was linearly related to the GA (GAel) value of the respective phenyl-substituted fluorinated alkanes. On the other hand, the corresponding correlation for the ρ values provided three lines for ArCH(Cl)R, ArCH(F)R and ArCH2R, respectively. These results supported our previous conclusion that the r− and ρ values are governed by the thermodynamic stability of the parent ion (ring substituent = H). Other factors arising from an atom bonded to the acidic center also influence the ρ value.

AB - The gas-phase acidities (GA) of 2-aryl-2-chloro-1,1,1-trifluoroethanes (1a), 2-aryl-2-fluoro-1,1,1-trifluoroethanes (2a), and related compounds, XC6H4CH(Z)R where Z = Cl (1) or F (2) and R = C2F5 (b), t-C4F9 (c), C(CF3)2C2F5 (d), C(CF3)2Me (e), Me (f), H (g), were investigated experimentally and computationally. On the basis of an excellent linear correlation (R2 > 0.99) of acidities of 1c, 1d, 1e, 1f and 2c, 2d, 2e, 2f where there is no fluorine atom at β-position to the deprotonation site with the corrected number of fluorine atoms contained in the fluorinated alkyl group, the extent of β-fluorine negative hyperconjugation of the CF3 and C2F5 groups (ΔGo β-F) was evaluated. The GAel values given by subtraction ΔGo β-F from the apparent GA value were considered to represent the electronic effect of the substituent X. The substituent effects on the GAel values and GA values for 1c, 1d, 1e, 1f and 2c, 2d, 2e, 2f were successfully analyzed in terms of the Yukawa–Tsuno equation. The variation of resonance demand parameter r− with the R group observed for various XC6H4CH(Z)R was linearly related to the GA (GAel) value of the respective phenyl-substituted fluorinated alkanes. On the other hand, the corresponding correlation for the ρ values provided three lines for ArCH(Cl)R, ArCH(F)R and ArCH2R, respectively. These results supported our previous conclusion that the r− and ρ values are governed by the thermodynamic stability of the parent ion (ring substituent = H). Other factors arising from an atom bonded to the acidic center also influence the ρ value.

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