Comparison of gas-phase acidities of some carbon acids with their rates of hydron exchange in methanolic methoxide

V.F. DeTuri, H.F. Koch, J.G. Koch, G. Lodder, M. Mishima, H. Zuilhof, N.M. Abrams, C.E. Anders, J.C. Biffinger, P. Han, A.R. Kurland, J.M. Nichols, A.M. Ruminski, P.R. Smith, K.D.J. Vasey

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Abstract

Hydron exchange reaction rates, k(exch)M(-1) s(-1), using methanolic sodium methoxide are compared with gas-phase acidities, Delta G(Acid)(0) kcal/mol, for four 9-YPhenylfluorenes-9-H-i, seven (YC6H4CH)-H-i(CF3)(2), seven YC6H4-(CHClCF3)-H-i, and (C6F5H)-H-i. Fourteen of the fluorinated benzylic compounds and pentafluorobenzene result in near unity experimental hydrogen isotope effects that suggest substantial amounts of internal return associated with the exchange process. Although the reactions of 9-phenylfluorene have experimental isotope effects that appear to be normal in value, they do not obey the Swain-Schaad relationship. This suggests that they occur with small amounts of internal return. The entropies of activation, Delta S-double dagger, are +12 to +14eu, for the benzylic compounds and different significantly from those for the 9-YPhenylfluorenes, Delta S-double dagger of -8 to - 12 eu. The Delta S-double dagger similar to 1 eu for the reactions of pentafluorobenzene falls between the other compounds. Density functional calculations using B3LYP/6-31+G(d,p) are reported for the reactions of CH3O-(HOCH3)(3) with C6F5H, C6H5CH(CF3)(2), C6H5CHClCF3, and 9-phenylfluorene. Copyright (c) 2006 John Wiley & Sons, Ltd.
Original languageEnglish
Pages (from-to)308-317
JournalJournal of Physical Organic Chemistry
Volume19
Issue number5
DOIs
Publication statusPublished - 2006

Fingerprint

Acidity
acidity
Isotopes
Carbon
Gases
vapor phases
acids
Acids
carbon
isotope effect
Reaction rates
Density functional theory
Methanol
Hydrogen
Entropy
Chemical activation
hydrogen isotopes
unity
reaction kinetics
sodium

Keywords

  • proton-transfer reactions
  • methanolic sodium methoxide
  • bronsted correlation
  • isotope exchange
  • hydrocarbons
  • mechanism
  • solvolysis
  • solvation
  • ketones
  • benzyl

Cite this

DeTuri, V.F. ; Koch, H.F. ; Koch, J.G. ; Lodder, G. ; Mishima, M. ; Zuilhof, H. ; Abrams, N.M. ; Anders, C.E. ; Biffinger, J.C. ; Han, P. ; Kurland, A.R. ; Nichols, J.M. ; Ruminski, A.M. ; Smith, P.R. ; Vasey, K.D.J. / Comparison of gas-phase acidities of some carbon acids with their rates of hydron exchange in methanolic methoxide. In: Journal of Physical Organic Chemistry. 2006 ; Vol. 19, No. 5. pp. 308-317.
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abstract = "Hydron exchange reaction rates, k(exch)M(-1) s(-1), using methanolic sodium methoxide are compared with gas-phase acidities, Delta G(Acid)(0) kcal/mol, for four 9-YPhenylfluorenes-9-H-i, seven (YC6H4CH)-H-i(CF3)(2), seven YC6H4-(CHClCF3)-H-i, and (C6F5H)-H-i. Fourteen of the fluorinated benzylic compounds and pentafluorobenzene result in near unity experimental hydrogen isotope effects that suggest substantial amounts of internal return associated with the exchange process. Although the reactions of 9-phenylfluorene have experimental isotope effects that appear to be normal in value, they do not obey the Swain-Schaad relationship. This suggests that they occur with small amounts of internal return. The entropies of activation, Delta S-double dagger, are +12 to +14eu, for the benzylic compounds and different significantly from those for the 9-YPhenylfluorenes, Delta S-double dagger of -8 to - 12 eu. The Delta S-double dagger similar to 1 eu for the reactions of pentafluorobenzene falls between the other compounds. Density functional calculations using B3LYP/6-31+G(d,p) are reported for the reactions of CH3O-(HOCH3)(3) with C6F5H, C6H5CH(CF3)(2), C6H5CHClCF3, and 9-phenylfluorene. Copyright (c) 2006 John Wiley & Sons, Ltd.",
keywords = "proton-transfer reactions, methanolic sodium methoxide, bronsted correlation, isotope exchange, hydrocarbons, mechanism, solvolysis, solvation, ketones, benzyl",
author = "V.F. DeTuri and H.F. Koch and J.G. Koch and G. Lodder and M. Mishima and H. Zuilhof and N.M. Abrams and C.E. Anders and J.C. Biffinger and P. Han and A.R. Kurland and J.M. Nichols and A.M. Ruminski and P.R. Smith and K.D.J. Vasey",
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DeTuri, VF, Koch, HF, Koch, JG, Lodder, G, Mishima, M, Zuilhof, H, Abrams, NM, Anders, CE, Biffinger, JC, Han, P, Kurland, AR, Nichols, JM, Ruminski, AM, Smith, PR & Vasey, KDJ 2006, 'Comparison of gas-phase acidities of some carbon acids with their rates of hydron exchange in methanolic methoxide', Journal of Physical Organic Chemistry, vol. 19, no. 5, pp. 308-317. https://doi.org/10.1002/poc.1057

Comparison of gas-phase acidities of some carbon acids with their rates of hydron exchange in methanolic methoxide. / DeTuri, V.F.; Koch, H.F.; Koch, J.G.; Lodder, G.; Mishima, M.; Zuilhof, H.; Abrams, N.M.; Anders, C.E.; Biffinger, J.C.; Han, P.; Kurland, A.R.; Nichols, J.M.; Ruminski, A.M.; Smith, P.R.; Vasey, K.D.J.

In: Journal of Physical Organic Chemistry, Vol. 19, No. 5, 2006, p. 308-317.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Comparison of gas-phase acidities of some carbon acids with their rates of hydron exchange in methanolic methoxide

AU - DeTuri, V.F.

AU - Koch, H.F.

AU - Koch, J.G.

AU - Lodder, G.

AU - Mishima, M.

AU - Zuilhof, H.

AU - Abrams, N.M.

AU - Anders, C.E.

AU - Biffinger, J.C.

AU - Han, P.

AU - Kurland, A.R.

AU - Nichols, J.M.

AU - Ruminski, A.M.

AU - Smith, P.R.

AU - Vasey, K.D.J.

PY - 2006

Y1 - 2006

N2 - Hydron exchange reaction rates, k(exch)M(-1) s(-1), using methanolic sodium methoxide are compared with gas-phase acidities, Delta G(Acid)(0) kcal/mol, for four 9-YPhenylfluorenes-9-H-i, seven (YC6H4CH)-H-i(CF3)(2), seven YC6H4-(CHClCF3)-H-i, and (C6F5H)-H-i. Fourteen of the fluorinated benzylic compounds and pentafluorobenzene result in near unity experimental hydrogen isotope effects that suggest substantial amounts of internal return associated with the exchange process. Although the reactions of 9-phenylfluorene have experimental isotope effects that appear to be normal in value, they do not obey the Swain-Schaad relationship. This suggests that they occur with small amounts of internal return. The entropies of activation, Delta S-double dagger, are +12 to +14eu, for the benzylic compounds and different significantly from those for the 9-YPhenylfluorenes, Delta S-double dagger of -8 to - 12 eu. The Delta S-double dagger similar to 1 eu for the reactions of pentafluorobenzene falls between the other compounds. Density functional calculations using B3LYP/6-31+G(d,p) are reported for the reactions of CH3O-(HOCH3)(3) with C6F5H, C6H5CH(CF3)(2), C6H5CHClCF3, and 9-phenylfluorene. Copyright (c) 2006 John Wiley & Sons, Ltd.

AB - Hydron exchange reaction rates, k(exch)M(-1) s(-1), using methanolic sodium methoxide are compared with gas-phase acidities, Delta G(Acid)(0) kcal/mol, for four 9-YPhenylfluorenes-9-H-i, seven (YC6H4CH)-H-i(CF3)(2), seven YC6H4-(CHClCF3)-H-i, and (C6F5H)-H-i. Fourteen of the fluorinated benzylic compounds and pentafluorobenzene result in near unity experimental hydrogen isotope effects that suggest substantial amounts of internal return associated with the exchange process. Although the reactions of 9-phenylfluorene have experimental isotope effects that appear to be normal in value, they do not obey the Swain-Schaad relationship. This suggests that they occur with small amounts of internal return. The entropies of activation, Delta S-double dagger, are +12 to +14eu, for the benzylic compounds and different significantly from those for the 9-YPhenylfluorenes, Delta S-double dagger of -8 to - 12 eu. The Delta S-double dagger similar to 1 eu for the reactions of pentafluorobenzene falls between the other compounds. Density functional calculations using B3LYP/6-31+G(d,p) are reported for the reactions of CH3O-(HOCH3)(3) with C6F5H, C6H5CH(CF3)(2), C6H5CHClCF3, and 9-phenylfluorene. Copyright (c) 2006 John Wiley & Sons, Ltd.

KW - proton-transfer reactions

KW - methanolic sodium methoxide

KW - bronsted correlation

KW - isotope exchange

KW - hydrocarbons

KW - mechanism

KW - solvolysis

KW - solvation

KW - ketones

KW - benzyl

U2 - 10.1002/poc.1057

DO - 10.1002/poc.1057

M3 - Article

VL - 19

SP - 308

EP - 317

JO - Journal of Physical Organic Chemistry

JF - Journal of Physical Organic Chemistry

SN - 0894-3230

IS - 5

ER -