Intramolecular Proton Transfer in the Isomerization of Hydroxyacetone: A Detailed Characterization Based on Reaction Force Analysis and the Bond Fragility Spectrum

Author(s):  
Wallace Derricotte ◽  
Huiet Joseph

The mechanism of isomerization of hydroxyacetone to 2-hydroxypropanal is studied within the framework of reaction force analysis at the M06-2X/6-311++G(d,p) level of theory. Three unique pathways are considered: (i) a step-wise mechanism that proceeds through formation of the Z-isomer of their shared enediol intermediate, (ii) a step-wise mechanism that forms the E-isomer of the enediol, and (iii) a concerted pathway that bypasses the enediol intermediate. Energy calculations show that the concerted pathway has the lowest activation energy barrier at 45.7 kcal mol<sup>-1</sup>. The reaction force, chemical potential, and reaction electronic flux are calculated for each reaction to characterize electronic changes throughout the mechanism. The reaction force constant is calculated in order to investigate the synchronous/asynchronous nature of the concerted intramolecular proton transfers involved. Additional characterization of synchronicity is provided by calculating the bond fragility spectrum for each mechanism.

2020 ◽  
Author(s):  
Wallace Derricotte ◽  
Huiet Joseph

The mechanism of isomerization of hydroxyacetone to 2-hydroxypropanal is studied within the framework of reaction force analysis at the M06-2X/6-311++G(d,p) level of theory. Three unique pathways are considered: (i) a step-wise mechanism that proceeds through formation of the Z-isomer of their shared enediol intermediate, (ii) a step-wise mechanism that forms the E-isomer of the enediol, and (iii) a concerted pathway that bypasses the enediol intermediate. Energy calculations show that the concerted pathway has the lowest activation energy barrier at 45.7 kcal mol<sup>-1</sup>. The reaction force, chemical potential, and reaction electronic flux are calculated for each reaction to characterize electronic changes throughout the mechanism. The reaction force constant is calculated in order to investigate the synchronous/asynchronous nature of the concerted intramolecular proton transfers involved. Additional characterization of synchronicity is provided by calculating the bond fragility spectrum for each mechanism.


2020 ◽  
Author(s):  
Huiet Joseph ◽  
Wallace Derricotte

The mechanism of isomerization of hydroxyacetone to 2-hydroxypropanal is studied within the framework of reaction force analysis at the M06-2X/6-311++G(d,p) level of theory. Three unique pathways are considered: (i) a step-wise mechanism that proceeds through formation of the Z-isomer of their shared enediol intermediate, (ii) a step-wise mechanism that forms the E-isomer of the enediol, and (iii) a concerted pathway that bypasses the enediol intermediate. Energy calculations show that the concerted pathway has the lowest activation energy barrier at 45.7 kcal mol<sup>-1</sup>. The reaction force, chemical potential, and reaction electronic flux are calculated for each reaction to characterize electronic changes throughout the mechanism. The reaction force constant is calculated in order to investigate the synchronous/asynchronous nature of the concerted intramolecular proton transfers involved. Additional characterization of synchronicity is provided by calculating the bond fragility spectrum for each mechanism.


Author(s):  
Mariko Tsukune ◽  
Yo Kobayashi ◽  
Takeharu Hoshi ◽  
Yasuyuki Shiraishi ◽  
Tomoyuki Miyashita ◽  
...  

2017 ◽  
Vol 56 (3) ◽  
Author(s):  
Stefan Vogt-Geisse ◽  
Soledad Gutiérrez-Oliva ◽  
Bárbara Herrera ◽  
Alejandro Toro-Labbé

In the framework of the reaction force analysis a study of the mechanism of the 1-3 intramolecular proton transfer in free and Mg (II) coordinated Thymine was done in terms of the reaction electronic flux and Wiberg bond orders. Profiles of these properties evidentiated differences between the proton transfer mechanisms induced by the presence of Mg(II) cation. A significative lowering in the activation energy put forward the catalytic effect of Mg. The reaction force analysis allows a precise identification of the catalytic effect thus uncovering the physical nature of activation energies. While in the free Thymine electronic polarization and transfer processes are present separately, in the Mg(II) coordinated Thymine both effects are observed simultaneously and are localized on the ring in the molecular topology. It is argued that the difference in the charge transfer mechanism leads to a more stable enol form in the Mg(II) coordinated Thymine.


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