DFT Investigation of Hydrogen Atom Abstraction from NHC-Boranes by Methyl, Ethyl and Cyanomethyl Radicals—Composition and Correlation Analysis of Kinetic Barriers
Understanding the hydrogen atom abstraction (HAA) reactions of <i>N</i>-heterocyclic carbene (NHC)-boranes is essential for extending the practical applications of boron chemistry. In this study, density functional theory (DFT) computations were performed for the HAA reactions of a serie...
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MDPI AG
2020-10-01
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| author | Hong-jie Qu Lang Yuan Cai-xin Jia Hai-tao Yu Hui Xu |
| author_facet | Hong-jie Qu Lang Yuan Cai-xin Jia Hai-tao Yu Hui Xu |
| author_sort | Hong-jie Qu |
| collection | DOAJ |
| description | Understanding the hydrogen atom abstraction (HAA) reactions of <i>N</i>-heterocyclic carbene (NHC)-boranes is essential for extending the practical applications of boron chemistry. In this study, density functional theory (DFT) computations were performed for the HAA reactions of a series of NHC-boranes attacked by <sup>•</sup>CH<sub>2</sub>CN, Me<sup>•</sup> and Et<sup>•</sup> radicals. Using the computed data, we investigated the correlations of the activation and free energy barriers with their components, including the intrinsic barrier, the thermal contribution of the thermodynamic reaction energy to the kinetic barriers, the activation Gibbs free energy correction and the activation zero-point vibrational energy correction. Furthermore, to describe the dependence of the activation and free energy barriers on the thermodynamic reaction energy or reaction Gibbs free energy, we used a three-variable linear model, which was demonstrated to be more precise than the two-variable Evans–Polanyi linear free energy model and more succinct than the three-variable Marcus-theory-based nonlinear HAA model. The present work provides not only a more thorough understanding of the compositions of the barriers to the HAA reactions of NHC-boranes and the HAA reactivities of the substrates but also fresh insights into the suitability of various models for describing the relationships between the kinetic and thermodynamic physical quantities. |
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| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-03-10T15:53:43Z |
| publishDate | 2020-10-01 |
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| spelling | doaj.art-3a3e7657379a47f78d842730ec03f4d72023-11-20T15:48:10ZengMDPI AGMolecules1420-30492020-10-012519450910.3390/molecules25194509DFT Investigation of Hydrogen Atom Abstraction from NHC-Boranes by Methyl, Ethyl and Cyanomethyl Radicals—Composition and Correlation Analysis of Kinetic BarriersHong-jie Qu0Lang Yuan1Cai-xin Jia2Hai-tao Yu3Hui Xu4Key Laboratory of Functional Inorganic Material Chemistry (Ministry of Education) and School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080, ChinaKey Laboratory of Functional Inorganic Material Chemistry (Ministry of Education) and School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080, ChinaKey Laboratory of Functional Inorganic Material Chemistry (Ministry of Education) and School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080, ChinaKey Laboratory of Functional Inorganic Material Chemistry (Ministry of Education) and School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080, ChinaKey Laboratory of Functional Inorganic Material Chemistry (Ministry of Education) and School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080, ChinaUnderstanding the hydrogen atom abstraction (HAA) reactions of <i>N</i>-heterocyclic carbene (NHC)-boranes is essential for extending the practical applications of boron chemistry. In this study, density functional theory (DFT) computations were performed for the HAA reactions of a series of NHC-boranes attacked by <sup>•</sup>CH<sub>2</sub>CN, Me<sup>•</sup> and Et<sup>•</sup> radicals. Using the computed data, we investigated the correlations of the activation and free energy barriers with their components, including the intrinsic barrier, the thermal contribution of the thermodynamic reaction energy to the kinetic barriers, the activation Gibbs free energy correction and the activation zero-point vibrational energy correction. Furthermore, to describe the dependence of the activation and free energy barriers on the thermodynamic reaction energy or reaction Gibbs free energy, we used a three-variable linear model, which was demonstrated to be more precise than the two-variable Evans–Polanyi linear free energy model and more succinct than the three-variable Marcus-theory-based nonlinear HAA model. The present work provides not only a more thorough understanding of the compositions of the barriers to the HAA reactions of NHC-boranes and the HAA reactivities of the substrates but also fresh insights into the suitability of various models for describing the relationships between the kinetic and thermodynamic physical quantities.https://www.mdpi.com/1420-3049/25/19/4509NHC-boraneshydrogen atom abstractioncorrelation analysiskinetic barrierbond dissociation energy |
| spellingShingle | Hong-jie Qu Lang Yuan Cai-xin Jia Hai-tao Yu Hui Xu DFT Investigation of Hydrogen Atom Abstraction from NHC-Boranes by Methyl, Ethyl and Cyanomethyl Radicals—Composition and Correlation Analysis of Kinetic Barriers Molecules NHC-boranes hydrogen atom abstraction correlation analysis kinetic barrier bond dissociation energy |
| title | DFT Investigation of Hydrogen Atom Abstraction from NHC-Boranes by Methyl, Ethyl and Cyanomethyl Radicals—Composition and Correlation Analysis of Kinetic Barriers |
| title_full | DFT Investigation of Hydrogen Atom Abstraction from NHC-Boranes by Methyl, Ethyl and Cyanomethyl Radicals—Composition and Correlation Analysis of Kinetic Barriers |
| title_fullStr | DFT Investigation of Hydrogen Atom Abstraction from NHC-Boranes by Methyl, Ethyl and Cyanomethyl Radicals—Composition and Correlation Analysis of Kinetic Barriers |
| title_full_unstemmed | DFT Investigation of Hydrogen Atom Abstraction from NHC-Boranes by Methyl, Ethyl and Cyanomethyl Radicals—Composition and Correlation Analysis of Kinetic Barriers |
| title_short | DFT Investigation of Hydrogen Atom Abstraction from NHC-Boranes by Methyl, Ethyl and Cyanomethyl Radicals—Composition and Correlation Analysis of Kinetic Barriers |
| title_sort | dft investigation of hydrogen atom abstraction from nhc boranes by methyl ethyl and cyanomethyl radicals composition and correlation analysis of kinetic barriers |
| topic | NHC-boranes hydrogen atom abstraction correlation analysis kinetic barrier bond dissociation energy |
| url | https://www.mdpi.com/1420-3049/25/19/4509 |
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