scholarly journals Experimental and Theoretical Study of Zirconocene-Catalyzed Oligomerization of 1-Octene

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1590
Author(s):  
Ilya Nifant’ev ◽  
Alexander Vinogradov ◽  
Alexey Vinogradov ◽  
Stanislav Karchevsky ◽  
Pavel Ivchenko
Keyword(s):  
Density Functional Theory ◽  
Quantum Chemical ◽  
Density Functional ◽  
Theoretical Study ◽  
Practical Interest ◽  
Equal Mass ◽  
Mass Ratio ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Olefin Oligomerization

Zirconocene-catalyzed coordination oligomerization of higher α-olefins is of theoretical and practical interest. In this paper, we present the results of experimental and theoretical study of α-olefin oligomerization, catalyzed by (η5-C5H5)]2ZrX2 1/1′ and O[SiMe2(η5-C5H4)]2ZrX2 2/2′ (X = Cl, Me) with the activation by modified methylalymoxane MMAO-12 or by perfluoroalkyl borate [PhNMe2H][B(C6F5)4] (NBF) in the presence and in the absence of organoaluminium compounds, Al(CH2CHMe2)3 (TIBA) and/or Et2AlCl. Under the conditions providing a conventional mononuclear reaction mechanism, 1′ catalyzed dimerization with low selectivity, while 2′ initiated the formation of oligomers in equal mass ratio. The presence of TIBA and especially Et2AlCl resulted in an increase of the selectivity of dimerization. Quantum chemical simulations of the main and side processes performed at the M-06x/ DGDZVP level of the density functional theory (DFT) allowed to explain experimental results involving traditional mononuclear and novel Zr-Al1 and Zr-Al2 mechanistic concepts.

scholarly journals Getting excited: challenges in quantum-classical studies of excitons in polymeric systems

2016 ◽  
Vol 18 (44) ◽  
pp. 30297-30304 ◽  
Author(s):  
Behnaz Bagheri ◽  
Björn Baumeier ◽  
Mikko Karttunen
Keyword(s):  
Molecular Dynamics ◽  
Density Functional Theory ◽  
Quantum Chemical ◽  
Density Functional ◽  
Phenylene Ethynylene ◽  
Many Body ◽  
Functional Theory ◽  
Polymeric Systems ◽  
The Density Functional Theory ◽  
Classical Studies

A combination of classical molecular dynamics (MM/MD) and quantum chemical calculations based on the density functional theory (DFT) and many-body Green's functions theory (GW-BSE) was performed to describe the conformational and optical properties of diphenylethyne (DPE), methylated-DPE and poly para phenylene ethynylene (PPE).

A theoretical study of α- and β-d-glucopyranose conformations by the density functional theory

2006 ◽  
Vol 419 (4-6) ◽  
pp. 326-332 ◽  
Author(s):  
Nobuaki Miura ◽  
Tohru Taniguchi ◽  
Kenji Monde ◽  
Shin-Ichiro Nishimura
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Theoretical Study ◽  
Functional Theory ◽  
The Density Functional Theory

scholarly journals CALCULATION OF THE ELECTRONIC STRUCTURE OF SOME EPOXY MOLECULES BY THE DFT METHOD

2021 ◽  
pp. 32-34
Author(s):  
V. A. Babkin ◽  
D. S. Andreev ◽  
E. S. Titova ◽  
A. V. Ignatov ◽  
R. O. Boldyrev ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Quantum Chemical Calculation ◽  
Quantum Chemical ◽  
Density Functional ◽  
Dft Method ◽  
Chemical Calculation ◽  
Functional Theory ◽  
The Density Functional Theory

In this work, we performed a quantum-chemical calculation of some epoxy molecules: 1,2-epoxy-butene, 1,2-epoxy-2-methylpropane, 1,2 epoxyethane by the density functional theory DFT. An optimized geometric and electronic structure of these compounds is obtained. It was found that the studied epoxides belong to the class of very weak СH-acids (pKa = 28-30).

scholarly journals Mechanism of Reactions of 1-Substituted Silatranes and Germatranes, 2,2-Disubstituted Silocanes and Germocanes, 1,1,1-Trisubstituted Hyposilatranes and Hypogermatranes with Alcohols (Methanol, Ethanol): DFT Study

Molecules ◽  
2020 ◽  
Vol 25 (12) ◽  
pp. 2803 ◽  
Author(s):  
Denis Chachkov ◽  
Rezeda Ismagilova ◽  
Yana Vereshchagina
Keyword(s):  
Density Functional Theory ◽  
Quantum Chemical ◽  
Density Functional ◽  
Activation Energies ◽  
Functional Theory ◽  
Gibbs Energies ◽  
The Density Functional Theory ◽  
Lower Activation ◽  
One Step ◽  
Intramolecular Hydrogen

The mechanism of reactions of silatranes and germatranes, and their bicyclic and monocyclic analogues with one molecule of methanol or ethanol, was studied at the Density Functional Theory (DFT) B3PW91/6-311++G(df,p) level of theory. Reactions of 1-substituted sil(germ)atranes, 2,2-disubstituted sil(germ)ocanes, and 1,1,1-trisubstituted hyposil(germ)atranes with alcohol (methanol, ethanol) proceed in one step through four-center transition states followed by the opening of a silicon or germanium skeleton and the formation of products. According to quantum chemical calculations, the activation energies and Gibbs energies of activation of reactions with methanol and ethanol are close, their values decrease in the series of atranes–ocanes–hypoatranes for interactions with both methanol and ethanol. The reactions of germanium-containing derivatives are characterized by lower activation energies in comparison with the reactions of corresponding silicon-containing compounds. The annular configurations of the product molecules with electronegative substituents are stabilized by the transannular N→X (X = Si, Ge) bond and different intramolecular hydrogen contacts with the participation of heteroatoms of substituents at the silicon or germanium.

scholarly journals What Differs on the Enzymatic Acetylation Mechanisms for Arylamines and Arylhydrazines Substrates? A Theoretical Study

2009 ◽  
Vol 2009 ◽  
pp. 1-5
Author(s):  
Qing-An Qiao ◽  
Xiao-Min Sun ◽  
Jie Jing ◽  
Xin Chen ◽  
Hua-Yang Wang ◽  
...  
Keyword(s):  
Experimental Data ◽  
Density Functional Theory ◽  
Density Functional ◽  
Theoretical Study ◽  
Transition States ◽  
Ring Structure ◽  
Membered Ring ◽  
Functional Theory ◽  
Lone Pairs ◽  
The Density Functional Theory

The acetylation mechanisms of several selected typical substrates from experiments, including arylamines and arylhydrazines, are investigated with the density functional theory in this paper. The results indicate that all the transition states are characterized by a four-membered ring structure, and hydralazine (HDZ) is the most potent substrate. The bioactivity for all the compounds is increased in a sequence ofPABA≈4-AS<4-MA<5-AS≈INH<HDZ. The conjunction effect and the delocalization of the lone pairs of N atom play a key role in the reaction. All the results are consistent with the experimental data.

Selective hydrogenation of cinnamaldehyde catalyzed by Co-doped Pt clusters: a density functional theoretical study

RSC Advances ◽  
2016 ◽  
Vol 6 (91) ◽  
pp. 88277-88286 ◽  
Author(s):  
Laicai Li ◽  
Wei Wei ◽  
Wei Wang ◽  
Xiaolan Wang ◽  
Lin Zhang ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Reaction Mechanism ◽  
Selective Hydrogenation ◽  
Density Functional ◽  
Theoretical Study ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Co Doped

The reaction mechanism of the selective hydrogenation of cinnamaldehyde catalyzed by pure Pt clusters and Co-doped Pt clusters was studied by the density functional theory.

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