scholarly journals Kinetics and mechanism of acyl transfer reactions. Part 15. Quantumchemicalsimulation of mechanisms of reactions of N-ethylaniline sulfonation

2019 ◽  
Vol 57 (2) ◽  
pp. 19-27
Author(s):  
Ludmila B. Kochetova ◽  
◽  
Tatiana P. Kustova ◽  
Keyword(s):  
Water Molecule ◽  
Transition State ◽  
Reaction Center ◽  
Three Dimensional ◽  
Axial Direction ◽  
Acyl Transfer ◽  
Nucleophilic Attack ◽  
Specific Solvation ◽  
Benzenesulfonyl Chloride ◽  
Trigonal Bipyramidal

The RHF/6-31G(d) quantum chemical simulation of the mechanism of the interaction of the secondary fatty aromatic amine N-ethylaniline with benzenesulfonyl chloride under conditions of non-specific water solvation, using the continuum model of the solvent, as well as of sulfonylation reactions of N-ethylaniline solvation complexes containing one water molecule, modeled specific solvation of N-ethylaniline with water, and one molecule of water and one of dioxane, which simulate the solvation of the amine with aqueous dioxane. Three-dimensional potential energy surface of these processes is calculated. It is shown that in the case of a reaction proceeding under conditions of non-specific solvation of reagents, the route with axial attack of the N-ethylaniline molecule to the sulfonyl reaction center is realized, in the two other cases the reactions proceed along a single route, starting as an axial attack of the nucleophile, which goes further with decreasing of the attack angle as reagent molecules approach each other. It was established that all the simulated reactions proceed in accordance with bimolecular coordinated mechanism of nucleophilic substitution SN2, which implies the formation of a single transition state in the reaction path. It was found that geometrical configuration of the reaction center in the transition state of N-ethylaniline reaction with benzenesulfonyl chloride under non-specific solvation by water is close to trigonal-bipyramidal, which is determined by the axial direction of the nucleophilic attack, in the two other cases it is medium between the trigonal-bipyramidal and tetragonal-pyramidal, which is associated with the change in the angle of N-ethylaniline attack as the reactant molecules approach each other. In a reaction involving N-ethylaniline monohydrate, a water molecule forms a 6-membered cyclic structure with reagent molecules in the transition state, in which the transfer of a proton from N-ethylaniline amino group to a hydrogen chloride molecule occurs via a relay mechanism involving the water molecule. The activation energy values of the studied processes were calculated; it is shown that both specific and universal solvation significantly lower the energy barrier of the reaction compared to the reaction occurring in gas phase, which is consistent with the data obtained earlier for related processes.

Kinetics and mechanism of acyl transfer reactions. Part 16. Quantum chemical simulation of mechanism of N-methylaniline sulfonation in aqueous 1,4-dioxane

2020 ◽  
Vol 61 (1) ◽  
pp. 1-8
Author(s):  
Ludmila B. Kochetova ◽  
◽  
Tatiana P. Kustova ◽  
Keyword(s):  
Water Molecule ◽  
Transition State ◽  
Reaction Center ◽  
Quantum Chemical ◽  
Acyl Transfer ◽  
Nucleophilic Attack ◽  
Quantum Chemical Simulation ◽  
Specific Solvation ◽  
Benzenesulfonyl Chloride ◽  
Chemical Simulation

The RHF/6-31G(d) quantum chemical simulation of the mechanism of the secondary fatty aromatic amine N-methylaniline interaction with benzenesulfonyl chloride under conditions of N-methylaniline specific solvation by one water molecule and one 1,4-dioxane molecule, and under conditions of N-methylaniline specific solvation by two water molecules and one 1,4-dioxane molecule. Three-dimensional potential energy surfaces of the processes pointed out are computed. It is shown that in the both cases a single route of the reactions is realized, starting as an axial nucleophilic attack, which goes further with decreasing of the attack angle as reagent molecules approach each other. It was established that both simulated reactions proceed in accordance with bimolecular concerted mechanism of nucleophilic substitution SN2, which implies the formation of a single transition state in the reaction path. It was found that geometrical configuration of the reaction center in the transition states of the reactions is medium between the trigonal-bipyramidal and tetragonal-pyramidal, which is associated with the change in the angle of N-methylaniline attack as the reactant molecules approach each other. In the benzenesulfonyl chloride reaction with N-methylaniline, solvated by one water molecule and one 1,4-dioxane molecule, the transition state is solvated only by 1,4-dioxane molecule, while water molecule moves away from the reaction center, whereas in the benzenesulfonyl chloride reaction with N-methylaniline, solvated by two water molecule and one 1,4-dioxane molecule the transition state is solvated by 1,4-dioxane molecule and one water molecule that forms hydrogen bond with chlorine atom and promote the S–Cl-bond loosening. The activation energies of the reactions were calculated; it is shown that specific solvation increases the reactions energetic barrier as compared with the reaction in gaseous phase, that is caused by the partial dehydratation of N-methylaniline molecule before the transition state formation. A decrease of the activation energy of the reaction with participation of N-methylaniline, solvated by two water molecule and one 1,4-dioxane molecule as compared with the cases of non-specific solvation of the reactants and N-methyl-aniline solvation by one water molecule and one 1,4-dioxane molecule is caused by the existence of the second water molecule in the system, forming a bond with amine group and facilitating N–H bond break.

Poly[aqua[μ4-3,3′-(diazenediyl)dibenzoato]zinc]

2012 ◽  
Vol 69 (1) ◽  
pp. 29-32 ◽  
Author(s):  
Lei-Lei Liu ◽  
Feng Zhao
Keyword(s):  
Water Molecule ◽  
Rotation Axis ◽  
Three Dimensional ◽  
Solvothermal Reaction ◽  
Coordination Geometry ◽  
One Dimensional ◽  
Trigonal Bipyramidal ◽  
Carboxylate Groups ◽  
Distorted Trigonal Bipyramidal Coordination ◽  
Distorted Trigonal Bipyramidal

The solvothermal reaction of Zn(OAc)2·2H2O with 3,3′-(diazenediyl)dibenzoic acid (H2ADB) in H2O at 393 K afforded the title complex, [Zn(C14H8N2O4)(H2O)]n. The asymmetric unit contains half a ZnIIcation, half an ADB ligand and half a water molecule. Each ZnIIcentre lies on a crystallographic twofold rotation axis and is five-coordinated by four O atoms of bridging carboxylate groups from four ADB ligands and one O atom from a water molecule, forming a distorted trigonal–bipyramidal coordination geometry. The [Zn(H2O)] subunits are bridged by carboxylate groups to give one-dimensional [Zn(μ-COO)4(H2O)]nchains. The chains are linked by ADB ligands into two-dimensional sheets, and these sheets are further connected to neighbouring sheetsviahydrogen bonds (OW—HW...O), forming a three-dimensional hydrogen-bond-stabilized structure with an unprecedented 374175262topology.

Structure Studies on Order Assemblage of Manganese II Isovanillin Complexes

2014 ◽  
Vol 618 ◽  
pp. 193-197
Author(s):  
Yu Liu ◽  
Shan Shan Zhang ◽  
Da Jun Song ◽  
Tian Zhu Yang ◽  
Hong Xiao Tian ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Water Molecule ◽  
Metal Complexes ◽  
Electrostatic Interaction ◽  
Supramolecular Structure ◽  
Significant Contribution ◽  
Three Dimensional ◽  
The Other ◽  
Trigonal Bipyramidal ◽  
Distorted Trigonal Bipyramidal

The ManganeseII Isovanillin complex [Mn2(C8H7O3)4(H2O)2], Diaqua-tetra (isovanillinato-O,O')-bis (manganeseII),the MnII atom is coordinated by three isovanillinate anions and one water molecule in a distorted trigonal bipyramidal configuration with five-coordinations geometry. And one isovanillinate ligand chelates to the MnII atom through its methyl and hydroxy O atoms, the other two isovanillinate ligand chelates to the MnII atom only through its hydroxy O atoms. The same as another MnII atom. So we get a Binuclear MnII metal complexe. The fact clearly suggests not so much significant contribution from the electrostatic interaction in the Mn-O bonding in Binuclear MnII metal complexes as we gotten in mononuclear MnII metal complexes. Adjacent complex link to each other via hydrogen bonds forming the three-dimensional supramolecular structure.

scholarly journals A new polymorph of aquabis(1,10-phenanthroline-κ2N,N′)copper(II) dinitrate

2014 ◽  
Vol 70 (5) ◽  
pp. m185-m186 ◽  
Author(s):  
Mehdi Boutebdja ◽  
Asma Lehleh ◽  
Adel Beghidja ◽  
Zouaoui Setifi ◽  
Hocine Merazig
Keyword(s):  
Hydrogen Bonds ◽  
Water Molecule ◽  
Three Dimensional ◽  
Space Groups ◽  
Trigonal Bipyramidal Geometry ◽  
Trigonal Bipyramidal ◽  
Dimensional Network ◽  
Title Molecule ◽  
Nitrate Anions ◽  
Phenanthroline Ligands

The title molecule, [Cu(C12H8N2)2(H2O)](NO3)2, is a new polymorph of a compound which up to now has been reported to crystallize space groups inC2/candCc. The crystal studied was twinned by non-merohedry (final BASF factor of 0.40043) with the structure being solved and refined inP-1. The CuIIatom is coordinated by four N atoms from two 1,10-phenanthroline ligands and an O atom from a water molecule in an approximate trigonal–bipyramidal geometry. Discrete entities of one cation and two nitrate anions are formed by water–nitrate O—H...O hydrogen bonds. The components are further assembled into a three-dimensional network by C—H...O hydrogen bonds.

Bis{tris[(1H-benzimidazol-3-ium-2-yl)methyl]amine} tetraaquaocta-μ2-chlorido-octachloridopentacadmate(II) monohydrate

2013 ◽  
Vol 69 (8) ◽  
pp. 811-814
Author(s):  
Chun-Hua Yu ◽  
Run-Qiang Zhu ◽  
Yu Jin ◽  
Ming-Liang Liu ◽  
Lei Jin
Keyword(s):  
Water Molecule ◽  
Three Dimensional ◽  
Water Molecules ◽  
Supramolecular Network ◽  
Methyl Amine ◽  
Trigonal Bipyramidal ◽  
Compound C ◽  
Distorted Octahedral ◽  
Chloride Ligand ◽  
Chloride Ligands

The title compound, (C24H24N7)2[Cd5Cl16(H2O)4]·H2O, contains a [Cd5Cl16(H2O)4]6−anion, two triply protonated tris[(1H-benzimidazol-3-ium-2-yl)methyl]amine cations and one solvent water molecule. The structure of the anion is a novel chloride-bridged pentanuclear cluster. The five unique CdIIcentres have quite different coordination environments. Two of the central hexacoordinated CdIIcations have a CdOCl5chromophore, in which each CdIIcation is ligated by four bridging chloride ligands, one terminal chloride ligand and one water molecule, adopting a distorted octahedral environment. The third central CdIIcation is octahedrally coordinated by four bridging chloride ligands and two water molecules. Finally, the two terminal CdIIcations are pentacoordinated by two bridging and three terminal chloride ligands and adopt a trigonal–bipyramidal geometry. A three-dimensional supramolecular network is formed through intra- and intermolecular O—H...O, O—H...Cl, N—H...Cl and N—H...O hydrogen bonds and π–π interactions between the cations and anions.<!?tpb=20.6pt>

Analysis of Vibration Caused by Electromagnetic Force on Stator End-Winding of Large Dry Submersible Motor

2013 ◽  
Vol 416-417 ◽  
pp. 428-432
Author(s):  
Li Shan ◽  
Xiao Wei Cheng ◽  
Yong Fang ◽  
Xiao Hua Bao
Keyword(s):  
Electromagnetic Field ◽  
Steady State ◽  
Transition State ◽  
Electromagnetic Force ◽  
Radial Displacement ◽  
Radial Direction ◽  
Axial Direction ◽  
Axial Displacement ◽  
Force Density ◽  
Submersible Motor

This paper investigates the vibration which caused by electromagnetic on the stator end-winding of the large dry submersible motor. Firstly, the electromagnetic field which included transition state and steady state is researched by 3-D FEM. Secondly, the electromagnetic force which lead to vibrations of end-winding is calculated by numerical method, it can be obtained that where endured the largest force density along the slant part of end-winding. Finally, the radial displacement and the axial displacement of the slant part which caused by vibrations is studied, the analysis results show that the axial displacement is larger than the amplitude of radial displacement. It indicates that the slant part of end-winding will be more easily damaged at axial direction than radial direction.

scholarly journals The first observation of 4D tomography measurement of plasma structures and fluctuations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chanho Moon ◽  
Kotaro Yamasaki ◽  
Yoshihiko Nagashima ◽  
Shigeru Inagaki ◽  
Takeshi Ido ◽  
...  
Keyword(s):  
Steady State ◽  
Three Dimensional ◽  
Axial Direction ◽  
Axial Position ◽  
Entire Cross Section ◽  
Helicon Plasma ◽  
Emission Profile ◽  
Dimensional Measurement ◽  
Tomography System ◽  
Three Dimensional Measurement

AbstractA tomography system is installed as one of the diagnostics of new age to examine the three-dimensional characteristics of structure and dynamics including fluctuations of a linear magnetized helicon plasma. The system is composed of three sets of tomography components located at different axial positions. Each tomography component can measure the two-dimensional emission profile over the entire cross-section of plasma at different axial positions in a sufficient temporal scale to detect the fluctuations. The four-dimensional measurement including time and space successfully obtains the following three results that have never been found without three-dimensional measurement: (1) in the production phase, the plasma front propagates from the antenna toward the end plate with an ion acoustic velocity. (2) In the steady state, the plasma emission profile is inhomogeneous, and decreases along the axial direction in the presence of the azimuthal asymmetry. Furthermore, (3) in the steady state, the fluctuations should originate from a particular axial position located downward from the helicon antenna.

scholarly journals Crystal structures of [Mn(bdc)(Hspar)2(H2O)0.25]·2H2O containing MnO6+1capped trigonal prisms and [Cu(Hspar)2](bdc)·2H2O containing CuO4squares (Hspar = sparfloxacin and bdc = benzene-1,4-dicarboxylate)

2016 ◽  
Vol 72 (1) ◽  
pp. 96-101
Author(s):  
Zhe An ◽  
Jing Gao ◽  
William T. A. Harrison
Keyword(s):  
Hydrogen Bonds ◽  
Water Molecule ◽  
Crystal Structures ◽  
Metal Ion ◽  
Three Dimensional ◽  
Trigonal Prism ◽  
Planar Geometry ◽  
Cationic Complex ◽  
Counter Ion ◽  
Square Planar

The syntheses and crystal structures of 0.25-aqua(benzene-1,4-dicarboxylato-κ2O,O′)bis(sparfloxacin-κ2O,O′)manganese(II) dihydrate, [Mn(C8H4O4)(C19H22F2N4O3)2(H2O)0.25]·2H2O or [Mn(bdc)(Hspar)2(H2O)0.25]·2H2O, (I), and bis(sparfloxacin-κ2O,O′)copper(II) benzene-1,4-dicarboxylate dihydrate, [Cu(C19H22F2N4O3)2](C8H4O4)·2H2O or [Cu(Hspar)2](bdc)·2H2O, (II), are reported (Hspar = sparfloxacin and bdc = benzene-1,4-dicarboxylate). The Mn2+ion in (I) is coordinated by twoO,O′-bidentate Hspar neutral molecules (which exist as zwitterions) and anO,O′-bidentate bdc dianion to generate a distorted MnO6trigonal prism. A very long bond [2.580 (12) Å] from the Mn2+ion to a 0.25-occupied water molecule projects through a square face of the prism. In (II), the Cu2+ion lies on a crystallographic inversion centre and a CuO4square-planar geometry arises from its coordination by twoO,O′-bidentate Hspar molecules. The bdc dianion acts as a counter-ion to the cationic complex and does not bond to the metal ion. The Hspar ligands in both (I) and (II) feature intramolecular N—H...O hydrogen bonds, which closeS(6) rings. In the crystals of both (I) and (II), the components are linked by N—H...O, O—H...O and C—H...O hydrogen bonds, generating three-dimensional networks.

Free Vibrations of Thick, Complete Conical Shells of Revolution From a Three-Dimensional Theory

2005 ◽  
Vol 72 (5) ◽  
pp. 797-800 ◽  
Author(s):  
Jae-Hoon Kang ◽  
Arthur W. Leissa
Keyword(s):  
Ritz Method ◽  
Three Dimensional ◽  
Axial Direction ◽  
Free Vibrations ◽  
Mode Shapes ◽  
Vibration Frequencies ◽  
Shells Of Revolution ◽  
Dimensional Theory ◽  
Conical Shells ◽  
Cylindrical Coordinate

A three-dimensional (3D) method of analysis is presented for determining the free vibration frequencies and mode shapes of thick, complete (not truncated) conical shells of revolution in which the bottom edges are normal to the midsurface of the shells based upon the circular cylindrical coordinate system using the Ritz method. Comparisons are made between the frequencies and the corresponding mode shapes of the conical shells from the authors' former analysis with bottom edges parallel to the axial direction and the present analysis with the edges normal to shell midsurfaces.

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