scholarly journals Computational study on the mechanism of metal-free photochemical borylation of aryl halides

2021 ◽  
Author(s):  
Chenhao Tu ◽  
Nana Ma ◽  
Qingli Xu ◽  
Wenyue Guo ◽  
Lanxin Zhou ◽  
...  
Keyword(s):  
Density Functional ◽  
Uv Light ◽  
Computational Study ◽  
Halogen Bond ◽  
Bond Cleavage ◽  
Aryl Halides ◽  
Homolytic Cleavage ◽  
Functional Theory ◽  
Aryl Radicals

C-radical borylation is an significant approach for the construction of carbon−boron bond. Photochemical borylation of aryl halides successfully applied this strategy. However, precise mechanisms, such as the generation of aryl radicals and the role of base additive(TMDAM) and water, remain controversy in these reactions. In this study, photochemical borylation of aryl halides has been researched by density functional theory (DFT) calculations. Indeed, the homolytic cleavage of the C−X bond under irradiation with UV-light is a key step for generation of aryl radicals. Nevertheless, the generation of aryl radicals may also undergo the process of single electron transfer and the heterolytic carbon-halogen bond cleavage sequence, and the latter is favorable during the reaction.

On the role of the surface oxygen species during A–H (A = C, N, O) bond activation: a density functional theory study

2015 ◽  
Vol 51 (13) ◽  
pp. 2621-2624 ◽  
Author(s):  
Jong Suk Yoo ◽  
Tuhin S. Khan ◽  
Frank Abild-Pedersen ◽  
Jens K. Nørskov ◽  
Felix Studt
Keyword(s):  
Density Functional ◽  
Bond Activation ◽  
Bond Cleavage ◽  
Oxygen Species ◽  
Final States ◽  
Surface Oxygen ◽  
Density Functional Theory Study ◽  
Reaction Energy ◽  
Functional Theory

During A–H (A = C, N, O) bond cleavage on O* or OH* pre-covered (111) surfaces, the oxygen species play the role of modifying the reaction energy by changing the species involved in the initial and final states of the reaction.

Mechanistic insight into the selective trans-1,4-polymerization of butadiene by terpyridine–iron(II) complexes — A computational study

2009 ◽  
Vol 87 (10) ◽  
pp. 1392-1405 ◽  
Author(s):  
Sven Tobisch
Keyword(s):  
Density Functional ◽  
Computational Study ◽  
Dft Method ◽  
Chain Growth ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Insertion Mechanism ◽  
Trans Regulation ◽  
Insight Into

The density functional theory (DFT) method has been employed to unravel mechanistic intricacies of the 1,4-polymerization of 1,3-butadiene mediated by the [(η3-RC3H4)FeII(C15H11N3)(η2-C4H6)]+ terpyridine–iron(II) active catalyst species. The π-allyl-insertion mechanism is operative for chain growth, whilst the alternative σ-allyl-insertion mechanism has been explicitly demonstrated as being inoperable. This study elucidates the mechanism of cis–trans regulation and unveils the factors that govern the observed high trans-1,4 stereoselectivity, in particular, the discriminative role of allylic isomerization. An atactic trans-1,4-polydiene is expected from polymerization of a terminally monosubstituted butadiene, the experimental results of which have not been reported thus far.

Theoretical study of NHC-catalyzed C-S bond cleavage and reconstruction reaction: Mechanism, stereoselectivity, and role of catalyst

2021 ◽  
Author(s):  
Yang Wang ◽  
Yue Liu ◽  
Kaili Gong ◽  
Han Zhang ◽  
Yu Lan ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Reaction Mechanism ◽  
Density Functional ◽  
Theoretical Study ◽  
Bond Cleavage ◽  
Functional Theory

A theoretical study of the mechanism of the N-heterocyclic carbene (NHC)-catalyzed C-S bond cleavage and reconstruction reaction of unsaturated thioesters was conducted using density functional theory (DFT). The origin of...

COMPUTATIONAL STUDY OF UNIMOLECULAR DECOMPOSITION MECHANISM OF RDX EXPLOSIVE

2007 ◽  
Vol 06 (02) ◽  
pp. 341-351 ◽  
Author(s):  
MIN HSIEN LIU ◽  
GEN FA ZHENG
Keyword(s):  
Density Functional ◽  
Computational Study ◽  
Bond Breaking ◽  
Computational Results ◽  
Unimolecular Decomposition ◽  
Homolytic Cleavage ◽  
Trans Form ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Bonding Site

This study investigated the RDX (1,3,5-Trinitro-1,3,5-triazine) molecule to elucidate its possible decomposition species and the corresponding energies by performing the density-functional theory (DFT) calculations. Reasonable decomposition mechanisms are proposed based on the bond energy calculated using the differential overlap (INDO) program, which yields the weakest bonding site for reference and determines the site of easy cleavage. Computational results indicate that the activation energy of direct cis-form HONO elimination is lower than that of direct trans-form HONO elimination and that of a two-stage elimination of two forms of HONO ( N – N bond fission combined with C – H bond breaking) in the initial decomposition step, which are 213.9 kJ/mol and 93.8–101.8 kJ/mol, respectively. Two possible pathways are proposed; (1) N – N bond homolytic cleavage followed by elimination of cis-form HONO, and (2) N – N bond homolytic cleavage followed by elimination of trans-form HONO.

scholarly journals Homolytic C-NO2 Bond Cleavage in Diaminodinitroethylene Isomers - A DFT Treatment

2020 ◽  
pp. 115-136
Author(s):  
Lemi Türker
Keyword(s):  
Density Functional Theory ◽  
Transition State ◽  
Quantum Chemical ◽  
Density Functional ◽  
Bond Cleavage ◽  
Chemical Properties ◽  
Bond Rupture ◽  
Homolytic Cleavage ◽  
Functional Theory ◽  
The One

Diaminodinitroethylene (DADNE) has three isomers including the well known geminal isomer, FOX-7. In the present study, the homolytic cleavage of one of the C-NO2 bonds of these isomers has been considered within the constraints of density functional theory at the level of UB3LYP/6-311++G(d,p). Transition states for that type of bond rupture are obtained. Various quantum chemical properties of the parent compounds and the decomposed systems are obtained, compared and discussed. Also the activation energies are calculated. The transition state originating from cis DADNE and the one from the geminal DADNE are found to be the most and least stable ones, respectively among the all.

Tetrahydroxydiboron-Initiated Atom-Transfer Radical Cyclization

Synthesis ◽  
2021 ◽  
Author(s):  
Pengfei Wang ◽  
Yuli Li ◽  
Guangwei Wang
Keyword(s):  
Density Functional ◽  
Bond Cleavage ◽  
Radical Cyclization ◽  
Lewis Base ◽  
Atom Transfer ◽  
Functional Theory ◽  
Energy Diagram ◽  
Free Energy Diagram ◽  
Atom Transfer Radical Cyclization

In this work, the first diboron reagent initiated atom-transfer radical cyclization was reported, in which the boryl radicals were generated by the homolytic cleavage of a B-B single bond weakened by the coordination of Lewis base. To clarify the role of carbonate and DMF in the cleavage of B-B bond, we calculated the free energy diagram of two pathways by density functional theory (DFT) investigations. The DFT calculation showed that the presence of carbonate facilitates the B-B bond cleavage to form boron radicals which can be further stabilized by DMF. Subsequent atom transfer cyclization initiated by stabilized dihydroxyboron radical are also energetically favored.

The Nature of S-N Bonding in Sulfonamides and Related Compounds: Insights into π-Bonding Contributions from Sulfur K-Edge XAS

2020 ◽  
Author(s):  
Tulin Okbinoglu ◽  
Pierre Kennepohl
Keyword(s):  
Density Functional ◽  
Chemical Properties ◽  
Functional Theory ◽  
Rotational Barriers ◽  
Td Dft ◽  
Nitrogen Bonds ◽  
X Ray Absorption ◽  
Related Compounds ◽  
And Chemical Properties

Molecules containing sulfur-nitrogen bonds, like sulfonamides, have long been of interest due to their many uses and chemical properties. Understanding the factors that cause sulfonamide reactivity is important, yet their continues to be controversy regarding the relevance of S-N π bonding in describing these species. In this paper, we use sulfur K-edge x-ray absorption spectroscopy (XAS) in conjunction with density functional theory (DFT) to explore the role of S<sub>3p</sub> contributions to π-bonding in sulfonamides, sulfinamides and sulfenamides. We explore the nature of electron distribution of the sulfur atom and its nearest neighbors and extend the scope to explore the effects on rotational barriers along the sulfur-nitrogen axis. The experimental XAS data together with TD-DFT calculations confirm that sulfonamides, and the other sulfinated amides in this series, have essentially no S-N π bonding involving S<sub>3p</sub> contributions and that electron repulsion and is the dominant force that affect rotational barriers.

scholarly journals Computational Study of the Electron Spectra of Vapor-Phase Indole and Four Azaindoles

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1947
Author(s):  
Delano P. Chong
Keyword(s):  
Density Functional Theory ◽  
Vapor Phase ◽  
Density Functional ◽  
Computational Study ◽  
Geometry Optimization ◽  
The Other ◽  
Functional Theory ◽  
Electron Spectra

After geometry optimization, the electron spectra of indole and four azaindoles are calculated by density functional theory. Available experimental photoemission and excitation data for indole and 7-azaindole are used to compare with the theoretical values. The results for the other azaindoles are presented as predictions to help the interpretation of experimental spectra when they become available.

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