Transition state structure of the reaction of homolytic dissociation of the C-N bond and competition between dif erent mechanisms of the primary act of gas-phase monomolecular decomposition of nitrobenzene

Николаева, Е. В.; Егоров, Д Л; Чачков, Д. В.; Шамов, А. Г.; Храпковский, Г. М.

doi:10.1007/s11172-019-2585-1

Cited by 4 publications

(2 citation statements)

References 60 publications

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“…13,18,24,27 Second, the activation energy of the homolytic bond-breaking process can be challenging to calculate since the corresponding transition state (TS) can be especially difficult to locateor, in many cases, even nonexistent as the energy increases monotonically with the C−N distance until the dissociation is complete. This situation was found by Nikolaeva et al 67 who studied C−NO 2 homolysis in nitrobenzene at the B3LYP/6-31G(d,p) level of theory. Third, it has been proposed that the BDE is proportional toor even equal tothe activation energy for compounds where the resonance stabilization and the structure of the TS are relatively similar.…”

Section: ■ Introductionsupporting

confidence: 65%

Unimolecular Decomposition Reactions of Picric Acid and Its Methylated Derivatives─A DFT Study

et al. 2022

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To handle energetic materials safely, it is important to have knowledge about their sensitivity. Density functional theory (DFT) has proven a valuable tool in the study of energetic materials, and in the current work, DFT is employed to study the thermal unimolecular decomposition of 2,4,6-trinitrophenol (picric acid, PA), 3-methyl-2,4,6-trinitrophenol (methyl picric acid, mPA), and 3,5-dimethyl-2,4,6-trinitrophenol (dimethyl picric acid, dmPA). These compounds have similar molecular structures, but according to the literature, mPA is far less sensitive to impact than the other two compounds. Three pathways believed important for the initiation reactions are investigated at 0 and 298.15 K. We compare the computed energetics of the reaction pathways with the objective of rationalizing the unexpected sensitivity behavior. Our results reveal a few if any significant differences in the energetics of the three molecules, and thus do not reflect the sensitivity deviations observed in experiments. These findings point toward the potential importance of crystal structure, crystal morphology, bimolecular reactions, or combinations thereof on the impact sensitivity of nitroaromatics.

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Section: ■ Introductionsupporting

confidence: 65%

Unimolecular Decomposition Reactions of Picric Acid and Its Methylated Derivatives─A DFT Study

et al. 2022

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“…We focus our discussion on the relaxed potential energy surface (PES) scans, which allow geometry optimization at each incremental step and are more representative of the true energy barrier E a corresponding to the minimum-energy path (MEP) for homolytic bond dissociation Figure shows the normalized total electronic energies of the relaxed PES scans, where the E a for MEP of each fragmentation is determined by the highest energy point along the scan.…”

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confidence: 99%

Understanding Fragmentation of Organic Small Molecules in Atom Probe Tomography

Bingham

Proudian

Vyas

et al. 2021

J. Phys. Chem. Lett.

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In atom probe tomography of molecular organic materials, field ionization of either entire molecules or molecular fragments can occur, but the mechanism governing this behavior was not previously understood. This work explains when a doubly ionized small molecule organic material is expected to undergo fragmentation. We find that multiple detection events arising from post-ionization fragmentation of a parent molecular dication into two daughter ions is well explained by the free energy and geometries of the molecules computed using density functional theory. Of the systems studied, exergonic free energies for formation of the daughter ions, smaller activation energies for dissociation, and increases in bond length are all found to be quantitative predictors for ion fragmentation. This work expands the applicability of atom probe tomography to organic materials by increasing the fundamental understanding of processes occurring during this analysis technique.

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A quantum chemical study of the mechanism of thermal decomposition of N′-methoxy-N-methyldiazene N-oxide

et al. 2022

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Transition state structure of the reaction of homolytic dissociation of the C-N bond and competition between dif erent mechanisms of the primary act of gas-phase monomolecular decomposition of nitrobenzene

Cited by 4 publications

References 60 publications

Unimolecular Decomposition Reactions of Picric Acid and Its Methylated Derivatives─A DFT Study

Unimolecular Decomposition Reactions of Picric Acid and Its Methylated Derivatives─A DFT Study

Understanding Fragmentation of Organic Small Molecules in Atom Probe Tomography

A quantum chemical study of the mechanism of thermal decomposition of N′-methoxy-N-methyldiazene N-oxide

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