The Role of Reaction Force and Chemical Potential in Characterizing the Mechanism of Double Proton Transfer in the Adenine−Uracil Complex

2007 ◽  
Vol 111 (26) ◽  
pp. 5921-5926 ◽  
Author(s):  
Bárbara Herrera ◽  
Alejandro Toro-Labbé
Keyword(s):  
Proton Transfer ◽  
Chemical Potential ◽  
Reaction Force ◽  
Double Proton Transfer

scholarly journals Elucidating the Catalytic Role of Mg(II) in the Intramolecular Proton Transfer Reaction in Thymine

2017 ◽  
Vol 56 (3) ◽  
Author(s):  
Stefan Vogt-Geisse ◽  
Soledad Gutiérrez-Oliva ◽  
Bárbara Herrera ◽  
Alejandro Toro-Labbé
Keyword(s):  
Proton Transfer ◽  
Catalytic Effect ◽  
Reaction Force ◽  
Physical Nature ◽  
Proton Transfer Reaction ◽  
Intramolecular Proton Transfer ◽  
Force Analysis ◽  
Catalytic Role ◽  
The Difference

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.

Excited-State Double Proton Transfer in 3-Formyl-7-azaindole:  Role of thenπ*State in Proton-Transfer Dynamics

2000 ◽  
Vol 104 (39) ◽  
pp. 8863-8871 ◽  
Author(s):  
Pi-Tai Chou ◽  
Guo-Ray Wu ◽  
Ching-Yen Wei ◽  
Mei-Ying Shiao ◽  
Yun-I Liu
Keyword(s):  
Excited State ◽  
Proton Transfer ◽  
Double Proton Transfer

The mechanism of double proton transfer in dimers of uracil and 2-thiouracil-The reaction force perspective

2009 ◽  
Vol 30 (3) ◽  
pp. 389-398 ◽  
Author(s):  
Al Mokhtar Lamsabhi ◽  
Otilia Mó ◽  
Soledad Gutiérrez-Oliva ◽  
Patricia Pérez ◽  
Alejandro Toro-Labbé ◽  
...  
Keyword(s):  
Proton Transfer ◽  
Reaction Force ◽  
Double Proton Transfer

scholarly journals Role of intramolecular hydrogen bonding in the excited-state intramolecular double proton transfer (ESIDPT) of calix[4]arene: A TDDFT study

Open Physics ◽  
2016 ◽  
Vol 14 (1) ◽  
pp. 602-609 ◽  
Author(s):  
Se Wang ◽  
Zhuang Wang ◽  
Ce Hao
Keyword(s):  
Hydrogen Bonding ◽  
Excited State ◽  
Hydrogen Bonds ◽  
Proton Transfer ◽  
Ground State ◽  
Intramolecular Hydrogen Bonding ◽  
Intramolecular Hydrogen Bonds ◽  
Double Proton Transfer ◽  
Intramolecular Hydrogen

AbstractThe time-dependent density functional theory (TDDFT) method was performed to investigate the excited-state intramolecular double proton transfer (ESIDPT) reaction of calix[4]arene (C4A) and the role of the intramolecular hydrogen bonds in the ESIDPT process. The geometries of C4A in the ground state and excited states (S1, S2 and T1) were optimized. Four intramolecular hydrogen bonds formed in the C4A are strengthened or weakened in the S2 and T1 states compared to those in the ground state. Interestingly, upon excitation to the S1 state of C4A, two protons H1 and H2 transfer along the two intramolecular hydrogen bonds O1-H1···O2 and O2-H2···O3, while the other two protons do not transfer. The ESIDPT reaction breaks the primary symmetry of C4A in the ground state. The potential energy curves of proton transfer demonstrate that the ESIDPT process follows the stepwise mechanism but not the concerted mechanism. Findings indicate that intramolecular hydrogen bonding is critical to the ESIDPT reactions in intramolecular hydrogen-bonded systems.

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

2020 ◽  
Author(s):  
Wallace Derricotte ◽  
Huiet Joseph
Keyword(s):  
Chemical Potential ◽  
Reaction Force ◽  
Intramolecular Proton Transfer ◽  
Intermediate Energy ◽  
Force Analysis ◽  
Activation Energy Barrier ◽  
Detailed Characterization ◽  
Proton Transfers ◽  
Reaction Force Constant

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.

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