Solvent effect on the degree of (a)synchronicity in polar Diels-Alder reactions from the perspective of the reaction force constant analysis

Diana Yepes, Jorge I. Martínez-Araya, Pablo Jaque

Resultado de la investigación: Article

2 Citas (Scopus)

Resumen

In this work, we computationally evaluated the influence of six different molecular solvents, described as a polarizable continuum model at the M06-2X/6–31+G(d,p) level, on the activation barrier/reaction rate, overall energy change, TS geometry, and degree of (a)synchronicity of two concerted Diels-Alder cycloadditions of acrolein (R1) and its complex with Lewis acid acroleinBH3 (R2) to cyclopentadiene. In gas-phase, we found that both exothermicity and activation barrier are only reduced by about 2.0 kcal mol−1, and the asynchronicity character of the mechanism is accentuated when BH3 is included. An increment in the solvent’s polarity lowers the activation energy of R1 by 1.3 kcal mol−1, while for R2 the reaction rate is enhanced by more than 2000 times at room temperature (i.e., the activation energy decreases by 4.5 kcal mol−1) if the highest polar media is employed. Therefore, a synergistic effect is achieved when both external agents, i.e., Lewis acid catalyst and polar solvent, are included together. This effect was ascribed to the ability of the solvent to favor the encounter between cyclopentadiene and acroleinBH3. This was validated by the asymmetry of the TS which becomes highly pronounced when either both or just BH3 is considered or the solvent’s polarity is increased. Finally, the reaction force constant reveals that an increment in the solvent’s polarity is able to turn a moderate asynchronous mechanism of the formation of the new C-C σ-bonds into a highly asynchronous one.

Idioma originalEnglish
Número de artículo33
PublicaciónJournal of Molecular Modeling
Volumen24
N.º1
DOI
EstadoPublished - 1 ene 2018

Huella dactilar

Diels-Alder reactions
Cyclopentanes
Lewis Acids
polarity
Reaction rates
reaction kinetics
Activation energy
Chemical activation
activation
activation energy
Acrolein
acids
Cycloaddition
Acids
cycloaddition
encounters
Gases
asymmetry
vapor phases
continuums

ASJC Scopus subject areas

  • Catalysis
  • Computer Science Applications
  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Computational Theory and Mathematics
  • Inorganic Chemistry

Citar esto

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title = "Solvent effect on the degree of (a)synchronicity in polar Diels-Alder reactions from the perspective of the reaction force constant analysis",
abstract = "In this work, we computationally evaluated the influence of six different molecular solvents, described as a polarizable continuum model at the M06-2X/6–31+G(d,p) level, on the activation barrier/reaction rate, overall energy change, TS geometry, and degree of (a)synchronicity of two concerted Diels-Alder cycloadditions of acrolein (R1) and its complex with Lewis acid acroleinBH3 (R2) to cyclopentadiene. In gas-phase, we found that both exothermicity and activation barrier are only reduced by about 2.0 kcal mol−1, and the asynchronicity character of the mechanism is accentuated when BH3 is included. An increment in the solvent’s polarity lowers the activation energy of R1 by 1.3 kcal mol−1, while for R2 the reaction rate is enhanced by more than 2000 times at room temperature (i.e., the activation energy decreases by 4.5 kcal mol−1) if the highest polar media is employed. Therefore, a synergistic effect is achieved when both external agents, i.e., Lewis acid catalyst and polar solvent, are included together. This effect was ascribed to the ability of the solvent to favor the encounter between cyclopentadiene and acroleinBH3. This was validated by the asymmetry of the TS which becomes highly pronounced when either both or just BH3 is considered or the solvent’s polarity is increased. Finally, the reaction force constant reveals that an increment in the solvent’s polarity is able to turn a moderate asynchronous mechanism of the formation of the new C-C σ-bonds into a highly asynchronous one.",
keywords = "DFT calculations, Diels-Alder reactions, Lewis acid catalysts, Reaction force, Reaction force constant, Reaction mechanisms, Solvent effect, Synchronicity",
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T1 - Solvent effect on the degree of (a)synchronicity in polar Diels-Alder reactions from the perspective of the reaction force constant analysis

AU - Yepes, Diana

AU - Martínez-Araya, Jorge I.

AU - Jaque, Pablo

N1 - Enviada a pago 02-02-2018

PY - 2018/1/1

Y1 - 2018/1/1

N2 - In this work, we computationally evaluated the influence of six different molecular solvents, described as a polarizable continuum model at the M06-2X/6–31+G(d,p) level, on the activation barrier/reaction rate, overall energy change, TS geometry, and degree of (a)synchronicity of two concerted Diels-Alder cycloadditions of acrolein (R1) and its complex with Lewis acid acroleinBH3 (R2) to cyclopentadiene. In gas-phase, we found that both exothermicity and activation barrier are only reduced by about 2.0 kcal mol−1, and the asynchronicity character of the mechanism is accentuated when BH3 is included. An increment in the solvent’s polarity lowers the activation energy of R1 by 1.3 kcal mol−1, while for R2 the reaction rate is enhanced by more than 2000 times at room temperature (i.e., the activation energy decreases by 4.5 kcal mol−1) if the highest polar media is employed. Therefore, a synergistic effect is achieved when both external agents, i.e., Lewis acid catalyst and polar solvent, are included together. This effect was ascribed to the ability of the solvent to favor the encounter between cyclopentadiene and acroleinBH3. This was validated by the asymmetry of the TS which becomes highly pronounced when either both or just BH3 is considered or the solvent’s polarity is increased. Finally, the reaction force constant reveals that an increment in the solvent’s polarity is able to turn a moderate asynchronous mechanism of the formation of the new C-C σ-bonds into a highly asynchronous one.

AB - In this work, we computationally evaluated the influence of six different molecular solvents, described as a polarizable continuum model at the M06-2X/6–31+G(d,p) level, on the activation barrier/reaction rate, overall energy change, TS geometry, and degree of (a)synchronicity of two concerted Diels-Alder cycloadditions of acrolein (R1) and its complex with Lewis acid acroleinBH3 (R2) to cyclopentadiene. In gas-phase, we found that both exothermicity and activation barrier are only reduced by about 2.0 kcal mol−1, and the asynchronicity character of the mechanism is accentuated when BH3 is included. An increment in the solvent’s polarity lowers the activation energy of R1 by 1.3 kcal mol−1, while for R2 the reaction rate is enhanced by more than 2000 times at room temperature (i.e., the activation energy decreases by 4.5 kcal mol−1) if the highest polar media is employed. Therefore, a synergistic effect is achieved when both external agents, i.e., Lewis acid catalyst and polar solvent, are included together. This effect was ascribed to the ability of the solvent to favor the encounter between cyclopentadiene and acroleinBH3. This was validated by the asymmetry of the TS which becomes highly pronounced when either both or just BH3 is considered or the solvent’s polarity is increased. Finally, the reaction force constant reveals that an increment in the solvent’s polarity is able to turn a moderate asynchronous mechanism of the formation of the new C-C σ-bonds into a highly asynchronous one.

KW - DFT calculations

KW - Diels-Alder reactions

KW - Lewis acid catalysts

KW - Reaction force

KW - Reaction force constant

KW - Reaction mechanisms

KW - Solvent effect

KW - Synchronicity

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DO - 10.1007/s00894-017-3563-x

M3 - Article

AN - SCOPUS:85039914714

VL - 24

JO - Journal of Molecular Modeling

JF - Journal of Molecular Modeling

SN - 1610-2940

IS - 1

M1 - 33

ER -