scholarly journals Comparison of ±σ-hole and ±R˙-hole interactions formed by tetrel-containing complexes: a computational study

RSC Advances ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 4011-4021
Author(s):  
Mahmoud A. A. Ibrahim ◽  
Ebtisam M. Z. Telb
Keyword(s):  
Computational Study ◽  
First Time

The characteristics and nature of ±R˙-hole interactions were uncovered for the first time and compared to their ±σ-hole analogs in ˙TF3⋯ and W–T–F3⋯B/R˙/A complexes.

Computational Design and Analysis of Nitinol-Based Arch Wedge Support

2018 ◽  
Author(s):  
Tyler Stranburg ◽  
Yucheng Liu ◽  
Harish Chander ◽  
Adam Knight
Keyword(s):  
Boundary Conditions ◽  
Mechanical Response ◽  
Computational Study ◽  
Experimental Testing ◽  
Permanent Deformation ◽  
Computational Design ◽  
Element Analysis ◽  
Human Movements ◽  
First Time ◽  
Human Motions

A nitinol-based arch wedge support (AWS) was designed using computational approach. Finite element analysis (FEA) was performed to on this design to assess the influence of loading, boundary conditions, and thickness on the mechanical response of the computer-aid design (CAD) model. Five loading conditions caused by different human movements, two boundary conditions, and three thicknesses are involved in this computational study. FEA results showed that the presented AWS design can resist forces caused by different human motions without generating any permanent deformation. The study features the first time to design and evaluate a thin-walled nitinol AWS model. The results of this study form the background of prototyping and experimental testing of the design in the next phase.

The effect of the aliphatic carboxylate linkers on the electronic structures, chemical bonding and optical properties of the uranium-based metal–organic frameworks

RSC Advances ◽  
2015 ◽  
Vol 5 (34) ◽  
pp. 26735-26748 ◽  
Author(s):  
Saumitra Saha ◽  
Udo Becker
Keyword(s):  
Optical Properties ◽  
Detailed Analysis ◽  
Computational Methods ◽  
Chemical Bonding ◽  
Electronic Structures ◽  
Computational Study ◽  
Metal Organic Frameworks ◽  
Metal Organic ◽  
First Time

A series of uranyl containing aliphatic dicarboxylate structures is studied using computational methods. Our computational study provides a detailed analysis of these MOFs and explores the effect of linkers on their properties for the first time.

Oxido-molybdenum complexes obtained by Cl/O interchange between MoCl5 and carboxylic acids: a crystallographic, spectroscopic and computational study

2014 ◽  
Vol 43 (43) ◽  
pp. 16416-16423 ◽  
Author(s):  
Marco Bortoluzzi ◽  
Fabio Marchetti ◽  
Guido Pampaloni ◽  
Stefano Zacchini
Keyword(s):  
Carboxylic Acids ◽  
Computational Study ◽  
Molybdenum Complexes ◽  
First Time

The reactivity of MoCl5 with carboxylic acids has been elucidated for the first time. The reactions are featured by the chlorinating behaviour of MoCl5, rather than affording the respective carboxylato complexes.

Computational study on NHC-catalyzed enantioselective and chemoselective fluorination of aliphatic aldehydes

2017 ◽  
Vol 4 (10) ◽  
pp. 1987-1998 ◽  
Author(s):  
Yang Wang ◽  
Yan Qiao ◽  
Donghui Wei ◽  
Mingsheng Tang
Keyword(s):  
Computational Study ◽  
Mechanistic Study ◽  
Aliphatic Aldehydes ◽  
First Time

A mechanistic study on NHC-catalyzed enantioselective and chemoselective fluorination of aliphatic aldehydes has been performed for the first time.

MECHANISMS FOR THE DECOMPOSITION OF HYDROXYL-RADICAL-INDUCED CYTOSINE HYDROPEROXIDES: A COMPUTATIONAL STUDY

2013 ◽  
Vol 12 (04) ◽  
pp. 1350027 ◽  
Author(s):  
ZE-QIN CHEN ◽  
YING XUE
Keyword(s):  
Hydroxyl Radical ◽  
Computational Study ◽  
Chemical Properties ◽  
Basis Set ◽  
Stationary Points ◽  
Decomposition Products ◽  
Natural Processes ◽  
Full Optimization ◽  
Explicit Water ◽  
First Time

Hydroxyl-radical-induced damage to cytosine leads to a multitude of base modifications, which contribute to the natural processes of aging, mutagenesis and carcinogenesis. The stable products resulting from the main hydroxyl-radical-induced cytosine hydroperoxide, 5-hydroxy-6-hydroperoxyl-5,6-dihydrocytosine (5-OH-6-OOH-DHC), have been mapped out in the present work for the first time using ab initio calculations. Optimized geometries of all stationary structures in the gas phase were determined at the MP2 and B3LYP using the 6-31G(d) basis set and at the B3LYP/6-311++G(d,p) levels of theory. Energies were also determined at the G3MP2 level of theory. Meanwhile, full optimization of all stationary points were also performed in aqueous solution at the B3LYP/CPCM/6-31G(d) level of theory to evaluate the solvent effect. Three distinct possible pathways, pathways A–C, were evaluated. For pathway C, four channels, channels D–G, were characterized in turn. In each pathway, both the direct and the water-mediated processes were considered. The calculated results clearly manifest that (i) pathway C is kinetically favored over pathways A and B and is the most energetically feasible decomposition process of 5-OH-6-OOH-DHC; (ii) for pathway C, channels D, E and G are energetically feasible mechanisms and 6,7-dihydroxy-[1,3,5]triazepane-2,4-dione, 1-carbamoyl-2-oxo-4,5-dihydroxyimidazolidine, and biuret therefore are predicted to be the kinetically favored decomposition products of 5-OH-6-OOH-DHC; (iii) channel G may be kinetically favored over channels D and E and have the highest possibility to occur; (iv) the thermal decomposition of 5-OH-6-OOH-DHC can be significantly promoted by the presence of one explicit water molecule. Apart from characterizing the experimental products well, the main striking result of the present DFT computational study is the identification of a new theoretical optimum decomposition product, i.e. 6,7-dihydroxy-[1,3,5]triazepane-2,4-dione. The data and insights presented here have elucidated the chemical properties of 5-OH-6-OOH-DHC in free radical reactions and should facilitate to assess their mutagenic features.

Computational study of Cu2ZnSn(X1−xTex)4 (X = S, Se) for optoelectronic applications

2016 ◽  
Vol 30 (22) ◽  
pp. 1650137 ◽  
Author(s):  
Naeem Ullah ◽  
G. Murtaza ◽  
M. A. Iqbal ◽  
Asif Mahmood ◽  
R. Khenata
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Computational Study ◽  
Visible Region ◽  
Strong Response ◽  
Functional Theory ◽  
Lattice Constants ◽  
Minimization Procedure ◽  
First Time ◽  
Time Density

The [Formula: see text], [Formula: see text] and [Formula: see text] and their alloys have been frequently investigated experimentally owing to their suitable bandgap for the solar cell applications. For the first time, density functional theory is applied to explore the structural, electronic and optical properties of [Formula: see text] and [Formula: see text] [Formula: see text]. The energy minimization procedure reveals that the Kesterite phase is stable compared to the Stannite structure. Lattice constants of the compounds are in good agreement with the previous experimental results. The alloys have direct bandgaps which decrease by increasing the concentration of Te. The chemical bonding among the cations and anion is dominantly covalent. Electronic bandgap dependent optical properties like absorption coefficient and optical conductivity are studied in detail. The materials show strong response in the visible region of energy spectrum indicating the usefulness of these materials for optoelectronic devices.

scholarly journals Catechin and Curcumin interact with corona (2019-nCoV/SARS-CoV2) viral S protein and ACE2 of human cell membrane: insights from Computational study and implication for intervention

2020 ◽  
Author(s):  
Atala B. Jena ◽  
Namrata Kanungo ◽  
Vinayak Nayak ◽  
G.B.N. Chainy ◽  
Jagneshwar Dandapat
Keyword(s):  
Binding Energy ◽  
Preventive Intervention ◽  
Computational Study ◽  
Protein S ◽  
Cell Receptor ◽  
Receptor Binding Domain ◽  
S Protein ◽  
Host Cell Receptor ◽  
Recent Outbreak ◽  
First Time

Abstract The recent outbreak of the coronavirus (2019n-CoV) is an unprecedented threat for human health throughout the globe. In this regards development of a suitable intervention is the need of the hour. The viral spike protein (S-Protein) and the cognate host cell receptor ACE2 can prove to be effective. Here, through computational approaches we have reported two polyphenols, Catechin and Curcumin which have dual binding affinity i.e both the molecule binds to viral S-protein and as well as ACE2. Catechin binds with S-protein and ACE2 with binding energy of -10.5 Kcal/mol and -8.9 Kcal/mol, respectively. Catechin binds with a greater affinty than that of curcumin which has a binding energy of -7.9Kcal/mol and - 7.8Kcal/mol for S-protein and ACE2, respectively. While curcumin gets bound directly to receptor binding domain (RBD) of viral S-protein, catechin binds to near proximity of RBD sequence of S-protein. Molecular simulation study demonstrates that curcumin directly binds with RBD site of S-protein during 40-100ns. In contrast, catechin binds with S-protein near the RBD site and causes fluctuation in the amino acids present in the RBD and it’s near proximity. In conclusion, this computational study for the first time predicts the possibility of above two polyphenols, for therapeutic/preventive intervention.

scholarly journals Computational Study of the Stereoselectivity Profiles of the Diels-Alder Cycloaddition Reactions of Cyclopentadiene and Butadiene with Cyclopropenes

2020 ◽  
Author(s):  
Veejendra Yadav
Keyword(s):  
Density Functional ◽  
Computational Study ◽  
Theoretical Models ◽  
Diels Alder ◽  
Cycloaddition Reactions ◽  
Free Energies ◽  
Differential Activation ◽  
Activation Free Energy ◽  
The Difference ◽  
First Time

The <i>endo</i> and <i>exo</i> stereoselectivities of the Diels-Alder (DA) cycloaddition reactions of 3,3-disubstituted cyclopropenes with butadiene and cyclopentadiene, the latter for the first time, were investigated by means of density functional and quantum chemical calculations for a comparison. To establish distinction between the selectivites, activation free energies were systematically estimated in the gas phase and also in solvents. The differential activation free energies clearly predict exclusive <i>endo</i> configuration of the products formed from the reaction of the unsubstituted cyclopropene with butadiene and cyclopentadiene. However, the results were found to be markedly different for the substituted cyclopropenes from available experimental selectivities. It was also discovered that butadiene and cyclopentadiene are markedly different in their respective stereospecific product yields, nevertheless the difference between the two was only a methylene group. The failure of the differential activation free energy approach to predict the experimental stereoselectivities of the DA reactions of several perhalocyclopropenes with cyclopentadiene is probably due to yet insufficient development of the various theoretical models dealing with the <i>endo</i> and <i>exo</i> DA preferences.

Computational Investigation of High Velocity Penetration of Copper Subjected to Impact From Nickel Projectiles

2015 ◽  
Author(s):  
Yucheng Liu ◽  
Yangqing Dou ◽  
Youssef Hammi
Keyword(s):  
High Velocity ◽  
Computational Study ◽  
Computational Simulation ◽  
Copper Plate ◽  
Computational Investigation ◽  
Threshold Velocity ◽  
Macro Scale ◽  
Penetration Mechanism ◽  
First Time ◽  
Stress Patterns

A computational simulation of penetration between nickel projectile and copper plate with high velocity in macro scale has been built. It is the first time a comprehensive investigation of penetration between these two materials. A threshold velocity between a nickel projectile and a copper plate is determined by mathematical equation in this paper. ABAQUS/Explicit is used to verify this threshold velocity by setting different velocities under the same condition and displaying visual animation of penetration results. John-cook model has been chosen to represent two material plastic behaviors. The shapes of penetrator and target are shown in order to expose penetration procedure and phenomena. Stress patterns and perforation features are adopted to make a good understanding of Ni-Cu penetration mechanism from computational study.

Reversing the relative 3MLCT–3MC order in Fe(ii) complexes using cyclometallating ligands: a computational study aiming at luminescent Fe(ii) complexes

2015 ◽  
Vol 44 (30) ◽  
pp. 13498-13503 ◽  
Author(s):  
Isabelle M. Dixon ◽  
Fabienne Alary ◽  
Martial Boggio-Pasqua ◽  
Jean-Louis Heully
Keyword(s):  
Triplet State ◽  
Computational Study ◽  
Tridentate Ligands ◽  
First Time

Positioning two cyclometallating rings on the periphery of tridentate ligands has allowed us to design for the first time an iron(ii) complex bearing the lowest triplet state of MLCT nature.

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