A molecular electron density theory study of the insertion of CO into frustrated Lewis pair boron-amidines

A [4 + 1] cycloaddition reaction

Mar Rios-Gutierrez, Luis R. Domingo, René S. Rojas, Alejandro Toro-Labbé, Patricia Perez

Resultado de la investigación: Article

Resumen

The insertion of CO into hydrogenated boron-amidine 1 yielding five-membered diazaborolone (5DAB) 3 has been studied within the molecular electron density theory (MEDT) at the DFT ωB97X-D/6-311G(d,p) level. This is a domino process comprised of two consecutive reactions: (i) the dehydrogenation of 1 yielding the frustrated Lewis pair (FLP) boron-amidine 4, which quickly equilibrates with four-membered diazaborolone (4DAB) 2; and (ii) the addition of CO into FLP 4, yielding the final 5DAB 3. Analysis of the Gibbs free energies indicates that the extrusion of H2 demands a high ΔG of 28.6 kcal·mol-1, being endergonic by 6.7 kcal·mol-1. The subsequent addition of CO into FLP 4 presents a low ΔG of 15.0 kcal·mol-1; formation of 5DAB 3 being exergonic by -5.7 kcal·mol-1 from hydrogenated boron-amidine 1. An analysis of the bonding changes along the insertion of CO in a smaller FLP model indicates that this reaction can be considered a [4 + 1] cycloaddition reaction taking place via a five-membered pseudocyclic transition state associated with a two-stage one-step mechanism. Analysis of the conceptual DFT reactivity indices suggests that the initial attack of CO on FLP 4 is an acid/base process in which the carbenoid carbonyl character allows CO to participate as a Lewis base, rather than a nucleophilic/electrophilic interaction. The results arising from the analysis of the Parr functions, however, coincide with this behaviour.

Idioma originalEnglish
Páginas (desde-hasta)9214-9224
Número de páginas11
PublicaciónDalton Transactions
Volumen48
N.º25
DOI
EstadoPublished - 1 ene 2019

Huella dactilar

Amidines
Boron
Cycloaddition
Carbon Monoxide
Carrier concentration
Discrete Fourier transforms
Lewis Bases
Gibbs free energy
Dehydrogenation
Extrusion
Acids

ASJC Scopus subject areas

  • Inorganic Chemistry

Citar esto

Rios-Gutierrez, Mar ; Domingo, Luis R. ; Rojas, René S. ; Toro-Labbé, Alejandro ; Perez, Patricia. / A molecular electron density theory study of the insertion of CO into frustrated Lewis pair boron-amidines : A [4 + 1] cycloaddition reaction. En: Dalton Transactions. 2019 ; Vol. 48, N.º 25. pp. 9214-9224.
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title = "A molecular electron density theory study of the insertion of CO into frustrated Lewis pair boron-amidines: A [4 + 1] cycloaddition reaction",
abstract = "The insertion of CO into hydrogenated boron-amidine 1 yielding five-membered diazaborolone (5DAB) 3 has been studied within the molecular electron density theory (MEDT) at the DFT ωB97X-D/6-311G(d,p) level. This is a domino process comprised of two consecutive reactions: (i) the dehydrogenation of 1 yielding the frustrated Lewis pair (FLP) boron-amidine 4, which quickly equilibrates with four-membered diazaborolone (4DAB) 2; and (ii) the addition of CO into FLP 4, yielding the final 5DAB 3. Analysis of the Gibbs free energies indicates that the extrusion of H2 demands a high ΔG≠ of 28.6 kcal·mol-1, being endergonic by 6.7 kcal·mol-1. The subsequent addition of CO into FLP 4 presents a low ΔG≠ of 15.0 kcal·mol-1; formation of 5DAB 3 being exergonic by -5.7 kcal·mol-1 from hydrogenated boron-amidine 1. An analysis of the bonding changes along the insertion of CO in a smaller FLP model indicates that this reaction can be considered a [4 + 1] cycloaddition reaction taking place via a five-membered pseudocyclic transition state associated with a two-stage one-step mechanism. Analysis of the conceptual DFT reactivity indices suggests that the initial attack of CO on FLP 4 is an acid/base process in which the carbenoid carbonyl character allows CO to participate as a Lewis base, rather than a nucleophilic/electrophilic interaction. The results arising from the analysis of the Parr functions, however, coincide with this behaviour.",
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A molecular electron density theory study of the insertion of CO into frustrated Lewis pair boron-amidines : A [4 + 1] cycloaddition reaction. / Rios-Gutierrez, Mar; Domingo, Luis R.; Rojas, René S.; Toro-Labbé, Alejandro; Perez, Patricia.

En: Dalton Transactions, Vol. 48, N.º 25, 01.01.2019, p. 9214-9224.

Resultado de la investigación: Article

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T1 - A molecular electron density theory study of the insertion of CO into frustrated Lewis pair boron-amidines

T2 - A [4 + 1] cycloaddition reaction

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AU - Domingo, Luis R.

AU - Rojas, René S.

AU - Toro-Labbé, Alejandro

AU - Perez, Patricia

PY - 2019/1/1

Y1 - 2019/1/1

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AB - The insertion of CO into hydrogenated boron-amidine 1 yielding five-membered diazaborolone (5DAB) 3 has been studied within the molecular electron density theory (MEDT) at the DFT ωB97X-D/6-311G(d,p) level. This is a domino process comprised of two consecutive reactions: (i) the dehydrogenation of 1 yielding the frustrated Lewis pair (FLP) boron-amidine 4, which quickly equilibrates with four-membered diazaborolone (4DAB) 2; and (ii) the addition of CO into FLP 4, yielding the final 5DAB 3. Analysis of the Gibbs free energies indicates that the extrusion of H2 demands a high ΔG≠ of 28.6 kcal·mol-1, being endergonic by 6.7 kcal·mol-1. The subsequent addition of CO into FLP 4 presents a low ΔG≠ of 15.0 kcal·mol-1; formation of 5DAB 3 being exergonic by -5.7 kcal·mol-1 from hydrogenated boron-amidine 1. An analysis of the bonding changes along the insertion of CO in a smaller FLP model indicates that this reaction can be considered a [4 + 1] cycloaddition reaction taking place via a five-membered pseudocyclic transition state associated with a two-stage one-step mechanism. Analysis of the conceptual DFT reactivity indices suggests that the initial attack of CO on FLP 4 is an acid/base process in which the carbenoid carbonyl character allows CO to participate as a Lewis base, rather than a nucleophilic/electrophilic interaction. The results arising from the analysis of the Parr functions, however, coincide with this behaviour.

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