scholarly journals Theoretical investigation of Banert cascade reaction

2018 ◽  
Vol 5 (4) ◽  
pp. 171075 ◽  
Author(s):  
S. Bhattacharyya ◽  
K. Hatua
Keyword(s):  
Activation Energy ◽  
Density Functional Theory ◽  
Density Functional ◽  
Energy Parameter ◽  
Cascade Reaction ◽  
Sigmatropic Rearrangement ◽  
Functional Theory ◽  
Rate Determining Step ◽  
Rate Of Reaction ◽  
Reaction Proceeds

Computational inside of Banert cascade reaction for triazole formation is studied with B3LYP/6-31G(d,p) level of theory. The reaction proceeds mainly by SN2 initial chloride displacement rather than SN2′-type attack. Furthermore, according to the rate of reaction calculation, SN2 displacement is much faster than SN2′ displacement in the order of 8. The [3,3]-sigmatropic rearrangement for the conversion of propargyl azide into triazafulvene has been proved as the rate-determining step having highest activation energy parameter. Solvent effect on total course of reaction has been found negligible. Furthermore, effects of different density functional theory functionals and functional groups on activation energies of [3,3]-sigmatropic rearrangement of propargyl azide were also studied. BHHLYP, ω B97XD, M062X and BMK calculated Δ G ‡ are consistent with B3LYP.

scholarly journals Robust and efficient calculation of activation energy by automated path search and density functional theory

2021 ◽  
Vol 5 (3) ◽  
Author(s):  
Koki Ueno ◽  
Kazuhide Ichikawa ◽  
Kosei Sato ◽  
Daisuke Sugita ◽  
Satoshi Yotsuhashi ◽  
...  
Keyword(s):  
Activation Energy ◽  
Density Functional Theory ◽  
Density Functional ◽  
Functional Theory ◽  
Efficient Calculation ◽  
Path Search

A Density Functional Theory Study of the Isomerization of Substituted 2and#39;-hydroxychalcones to the Corresponding Flavanones

2021 ◽  
Vol 43 (1) ◽  
pp. 25-25
Author(s):  
Said Abdelqadar Said Said Abdelqadar Said ◽  
Omar A Shareef and Abdulkhalik S Alkazzaz Omar A Shareef and Abdulkhalik S Alkazzaz
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Ring Closure ◽  
Basis Set ◽  
Functional Theory ◽  
Rate Determining Step ◽  
The Density Functional Theory ◽  
Electronic And Structural Properties ◽  
Maximum Hardness Principle

The transformation of 2and#39;-hydroxychalcones to their corresponding flavanones was studied theoretically by the use of the density functional theory (DFT) with B3-LYP/ 6-311G basis set to get important information about the role of both of electronic and structural properties in this process. The obtained energies were found to be in agreement with our previous results that obtained from HPLC studies. The estimated hardness, polarizability, and electrophilicity profiles were found to obey the maximum hardness principle (MHP), minimum polarizability principle (MPP), and the minimum electrophilicity principle (MEP) respectively. Flavanone ring closure was found to be the rate-determining step.

scholarly journals Are boat transition states likely to occur in Cope rearrangements? A DFT study of the biogenesis of germacranes

2017 ◽  
Vol 13 ◽  
pp. 1969-1976 ◽  
Author(s):  
José Enrique Barquera-Lozada ◽  
Gabriel Cuevas
Keyword(s):  
Density Functional Theory ◽  
Transition State ◽  
Density Functional ◽  
Chair Conformation ◽  
High Energy ◽  
Functional Theory ◽  
Sigmatropic Rearrangements ◽  
The Density Functional Theory ◽  
Reaction Proceeds ◽  
Cope Rearrangements

It has been proposed that elemanes are biogenetically formed from germacranes by Cope sigmatropic rearrangements. Normally, this reaction proceeds through a transition state with a chair conformation. However, the transformation of schkuhriolide (germacrane) into elemanschkuhriolide (elemane) may occur through a boat transition state due to the final configuration of the elemanschkuhriolide, but this transition state is questionable due to its high energy. The possible mechanisms of this transformation were studied in the density functional theory frame. The mechanistic differences between the transformation of (Z,E)-germacranes and (E,E)-germacranes were also studied. We found that (Z,E)-germacranolides are significantly more stable than (E,E)-germacranolides and elemanolides. In the specific case of schkuhriolide, even when the boat transition state is not energetically favored, a previous hemiacetalization lowers enough the energetic barrier to allow the formation of a very stable elemanolide that is even more stable than its (Z,E)-germacrane.

DENSITY FUNCTIONAL THEORY STUDY ON THE MECHANISM OF TRIMETHYLAMINE-CATALYZED BAYLIS–HILLMAN REACTION

2010 ◽  
Vol 09 (supp01) ◽  
pp. 65-75 ◽  
Author(s):  
JING LI ◽  
WAN-YI JIANG
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Dft Method ◽  
Polarizable Continuum Model ◽  
Functional Theory ◽  
Reaction Barrier ◽  
Hydrogen Shift ◽  
Rate Determining Step ◽  
The Density Functional Theory ◽  
Polarizable Continuum

The trimethylamine-catalyzed Baylis–Hillman reaction of formaldehyde and vinylaldehyde has been studied with the density functional theory (DFT) method of B3LYP/6-31+G(d,p). In the gas phase, the reaction involves an amine–formaldehyde–vinylaldehyde trimolecular addition transition structure followed by rate-determining intramolecular 1,3-hydrogen shift. When a bulk solvent effect of water was considered with conductor-like polarizable continuum model (CPCM), the reaction was found to follow the sequence of Michael-addition of amine to vinylaldehyde (step 1), addition of formaldehyde (step 2), and 1,3-hydrogen shift (step 3), with the 1,3-hydrogen shift as rate-determining. The overall reaction barrier is significantly reduced. When a molecule of water is involved in the reaction, the 1,3-hydrogen shift is significantly promoted so that the rate-determining step becomes the C–C bond formation. The calculated overall reaction barrier is in agreement with experimental observations.

scholarly journals Understanding oxidative dehydrogenation of ethane on Co3O4 nanorods from density functional theory

2016 ◽  
Vol 6 (18) ◽  
pp. 6861-6869 ◽  
Author(s):  
Victor Fung ◽  
Franklin (Feng) Tao ◽  
De-en Jiang
Keyword(s):  
Density Functional Theory ◽  
Oxidative Dehydrogenation ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Rate Determining Step ◽  
Oxidative Dehydrogenation Of Ethane ◽  
Co3o4 Nanorods

Density functional theory calculations reveal the complete pathways of oxidative dehydrogenation of ethane to form ethene on the Co3O4(111) surface and the rate-determining step.

scholarly journals Electrical Conduction Characteristic of a 2D MXene Device with Cu/Cr2C/TiN Structure Based on Density Functional Theory

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3671
Author(s):  
Lei Wang ◽  
Jing Wen ◽  
Yuan Jiang ◽  
Qiaofeng Ou ◽  
Lei Yu ◽  
...  
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Density Functional Theory ◽  
Electrical Conduction ◽  
Density Functional ◽  
First Principle ◽  
Functional Theory ◽  
Lower Activation ◽  
Lower Activation Energy ◽  
Memristor Device

The electronic structure and the corresponding electrical conductive behavior of the Cu/Cr2C/TiN stack were assessed according to a newly developed first-principle model based on density functional theory. Using an additional Cr2C layer provides the metal-like characteristic of the Cu/Cr2C/TiN stack with much larger electrical conduction coefficients (i.e., mobility, diffusivity, and electrical conductivity) than the conventional Ag/Ti3C2/Pt stack due to the lower activation energy. This device is therefore capable of offering faster switching speeds, lower programming voltage, and better stability and durability than the memristor device with conventional Ti3C2 MXene.

scholarly journals Theoretical investigation on the effect of the ligand on bis-silylation of C(sp)–C(sp) by Ni complexes

RSC Advances ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 1005-1010
Author(s):  
Li Hui ◽  
He Yuhan ◽  
Wang Jiaqi
Keyword(s):  
Density Functional Theory ◽  
Reaction Mechanism ◽  
Transition Metal ◽  
Theoretical Investigation ◽  
Density Functional ◽  
Active Catalyst ◽  
Organic Ligand ◽  
Organic Complex ◽  
Functional Theory ◽  
Rate Determining Step

Density functional theory (DFT) is used to study the bis-silylation of alkynes catalyzed by a transition metal nickel–organic complex; the active catalyst, the organic ligand, the reaction mechanism, and rate-determining step are discussed in this paper.

A Density Functional Theory Study of the Isomerization of Substituted 2and#39;-hydroxychalcones to the Corresponding Flavanones

2021 ◽  
Vol 43 (1) ◽  
pp. 25-25
Author(s):  
Said Abdelqadar Said Said Abdelqadar Said ◽  
Omar A Shareef and Abdulkhalik S Alkazzaz Omar A Shareef and Abdulkhalik S Alkazzaz
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Ring Closure ◽  
Basis Set ◽  
Functional Theory ◽  
Rate Determining Step ◽  
The Density Functional Theory ◽  
Electronic And Structural Properties ◽  
Maximum Hardness Principle

The transformation of 2and#39;-hydroxychalcones to their corresponding flavanones was studied theoretically by the use of the density functional theory (DFT) with B3-LYP/ 6-311G basis set to get important information about the role of both of electronic and structural properties in this process. The obtained energies were found to be in agreement with our previous results that obtained from HPLC studies. The estimated hardness, polarizability, and electrophilicity profiles were found to obey the maximum hardness principle (MHP), minimum polarizability principle (MPP), and the minimum electrophilicity principle (MEP) respectively. Flavanone ring closure was found to be the rate-determining step.

Kinetic understanding of the effect of Na and Mg on pyrolytic behavior of lignin using a distributed activation energy model and density functional theory modeling

2019 ◽  
Vol 21 (5) ◽  
pp. 1099-1107 ◽  
Author(s):  
Kwang Ho Kim ◽  
Keunhong Jeong ◽  
Seung-Soo Kim ◽  
Robert C. Brown
Keyword(s):  
Activation Energy ◽  
Density Functional Theory ◽  
Density Functional ◽  
Alkaline Earth ◽  
Catalytic Effect ◽  
Energy Model ◽  
Alkaline Earth Metals ◽  
Distributed Activation Energy Model ◽  
Functional Theory ◽  
Naturally Occurring

The catalytic effect of Na and Mg, naturally occurring alkali and alkaline earth metals, on lignin pyrolysis was systematically analyzed using a distributed activation energy model and computational modeling.

Sign in / Sign up

Export Citation Format

Share Document