Structure Analysis of Catechol-Like Molecular Fragments

1993 ◽  
Vol 58 (6) ◽  
pp. 1242-1254
Author(s):  
Karel Huml ◽  
Pavel Soldán ◽  
Karel Zimmermann
Keyword(s):  
Potential Energy ◽  
Benzene Ring ◽  
Structure Analysis ◽  
Molecular Fragments ◽  
Torsion Angles ◽  
Energy Minimizer ◽  
Structure Correlation ◽  
Region Theory ◽  
Symmetry Operations ◽  
Good Agreement

A system of rigid benzene ring and two variable torsion angles ϕ(C-C-OH) in catechol-like molecular fragments was studied. A scattergam of the two torsion angles taken from the Cambridge Structural Databank is in a good agreement with the potential energy map calculated with the AMBER compatible energy minimizer ORAL. Symmetry operations and point symmetry domains used during the analysis are described in detail. Results are interpreted in accord with the catchment region theory and the structure-correlation principle.

Validity of the Finite Fracture Mechanics Based Asymptotic Analysis for Predictions of Crack Deflection in Thin Layers of Ceramic Laminates

2014 ◽  
Vol 627 ◽  
pp. 237-240 ◽  
Author(s):  
Oldřich Ševeček ◽  
Dominique Leguillon ◽  
Tomáš Profant ◽  
Michal Kotoul
Keyword(s):  
Potential Energy ◽  
Asymptotic Solution ◽  
Asymptotic Analysis ◽  
Crack Extension ◽  
Crack Deflection ◽  
Thin Layers ◽  
Reference Solution ◽  
Finite Fracture Mechanics ◽  
Higher Order Terms ◽  
Good Agreement

The work studies and compares different approaches suitable for predictions of the crack deflection (bifurcation) in ceramic laminates containing thin layers under high residual stresses and discuss a suitability and limits of using of the asymptotic analysis for such problems. The thickness of the thin compressive layers where the crack deflection occurs is only one order higher than the crack extension lengths considered within the solution. A purely FEM based calculation of the energy and stress conditions, necessary for the crack propagation, serves as the reference solution to the problem. The asymptotic analysis is used after for calculations of the same quantities (especially of energy release rate – ERR). This concept enables semi-analytical calculations of ERR or changes in potential energy induced by the crack extensions of different lengths and directions. Such approach can save a large amount of simulations and time compared with the pure FEM based calculations. It was found that the asymptotic analysis provides a good agreement for investigations of the crack increments enough far from the adjacent interfaces but for longer extensions (of length above 1/5-1/10 of the distance from the interface) starts more significantly to deviate from the correct solution. Involvement of the higher order terms in the asymptotic solution or other improvement of the model is thus advisable.

scholarly journals N-(4-Ethoxy-2,5-dinitrophenyl)acetamide

IUCrData ◽  
2020 ◽  
Vol 5 (8) ◽  
Author(s):  
Sannihith N. Uppu ◽  
Ogad A. Agu ◽  
Curtistine J. Deere ◽  
Frank R. Fronczek
Keyword(s):  
Hydrogen Bond ◽  
Nitro Group ◽  
Benzene Ring ◽  
Title Compound ◽  
The Other ◽  
Ring Plane ◽  
Torsion Angles ◽  
Compound C ◽  
Bifurcated Hydrogen Bond

In the title compound, C10H11N3O6, the torsion angles about the bonds to the benzene ring are less than 4°, except for the nitro groups, which are twisted out of the ring plane by 25.27 (3) and 43.63 (2)°. The N—H group forms a bifurcated hydrogen bond, with an intramolecular component to a nitro group O atom and an intermolecular component to the other nitro group, thereby forming chains propagating in the [010] direction. Several weak C—H...O interactions are also present.

scholarly journals Crystal structure ofN-(1-allyl-3-chloro-4-ethoxy-1H-indazol-5-yl)-4-methoxybenzenesulfonamide

2014 ◽  
Vol 70 (9) ◽  
pp. o1029-o1030
Author(s):  
Hakima Chicha ◽  
El Mostapha Rakib ◽  
Latifa Bouissane ◽  
Mohamed Saadi ◽  
Lahcen El Ammari
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Benzene Ring ◽  
Title Compound ◽  
Three Dimensional ◽  
Ring System ◽  
Torsion Angles ◽  
Compound C ◽  
Dimensional Network

In the title compound, C19H20ClN3O4S, the benzene ring is inclined to the indazole ring system (r.m.s. deviation = 0.014 Å) by 65.07 (8)°. The allyl and ethoxy groups are almost normal to the indazole ring, as indicated by the respective torsion angles [N—N—C—C = 111.6 (2) and C—C—O—C = −88.1 (2)°]. In the crystal, molecules are connected by N—H...N hydrogen bonds, forming helical chains propagating along [010]. The chains are linked by C—H...O hydrogen bonds, forming a three-dimensional network.

scholarly journals Double Pendulum Induced Stability

2015 ◽  
Vol 07 (06) ◽  
pp. 1550088
Author(s):  
Bezdenejnykh Nikolai ◽  
Andres Mateo Gabin ◽  
Raul Zazo Jimenez
Keyword(s):  
Theoretical Analysis ◽  
Potential Energy ◽  
High Frequency ◽  
Relative Equilibrium ◽  
Double Pendulum ◽  
Harmonic Vibrations ◽  
Hamilton Equations ◽  
High Frequency Harmonic ◽  
Good Agreement ◽  
Frequency Harmonic

In this work, a study of the relative equilibrium of a double pendulum whose point of suspension performs high frequency harmonic vibrations is presented. In order to determine the induced positions of equilibrium of the double pendulum at different gravity and vibration configurations, a set of experiments has been conducted. The theoretical analysis of the problem has been developed using Kapitsa’s method and numerical method. The method of Kapitsa allows to analyze the potential energy of a system in general and to find the values of the parameters of the problem that correspond to the relative extreme of energy — positions of stable or unstable equilibrium. The results of numerical and theoretical analysis of Hamilton equations are in good agreement with the results of the experiments.

QUASICLASSICAL TRAJECTORY CALCULATION OF THE CHEMICAL REACTION Ba + HI

2009 ◽  
Vol 08 (05) ◽  
pp. 827-835 ◽  
Author(s):  
LI YAO ◽  
YONGLU LIU ◽  
HAIYANG ZHONG ◽  
WANGHE CAO
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Cross Section ◽  
Reaction Cross Section ◽  
Energy Surface ◽  
Reaction Cross ◽  
Trajectory Calculation ◽  
Quasiclassical Trajectory Calculation ◽  
Rotational Distribution ◽  
Good Agreement

This paper reports the results of quasiclassical trajectory calculation on extended London-Eyring-Polanyi-Sato potential energy surface for the reaction between Ba atom and HI . The rotational distribution, vibrational distribution, reaction cross section, and rotational alignment are all obtained and they are under detailed discussion for product BaI . The calculated results are in good agreement with the experimental results.

Conformational behaviour of bridging diphenylphosphido ligands

1999 ◽  
Vol 55 (2) ◽  
pp. 203-208 ◽  
Author(s):  
John J. Barker ◽  
A. Guy Orpen
Keyword(s):  
Phenyl Ring ◽  
Global Minimum ◽  
Energy Surface ◽  
Low Energy ◽  
Block Element ◽  
Torsion Angles ◽  
Representative Species ◽  
Universal Force Field ◽  
Structural Database ◽  
Good Agreement

Data retrieved from the Cambridge Structural Database for crystal structures containing (μ-diphenylphosphido) metal complexes, [M 2{μ-PPh2}] (where M is a d-block element), have been analysed to evaluate the conformational behaviour of these species. The observed distribution of torsion angles about the P—C bonds has been compared with the potential energy surface (PES) for phenyl rotations in a representative species [(AuBr)2{μ-PPh2}]− computed using the universal force field. Good agreement was obtained between the low-energy (<8 kJ mol−1 above the global minimum) regions of the PES and the occupied regions of the two-dimensional P—Ph rotor conformation space. Phenyl ring rotations occur by coupled, geared disrotatory and uncoupled conrotatory motions of the phenyl groups in this and other classes of PPh2 rotors.

Density Functional Theory Study: Interactions of Lithium-Montmorillonite with Poly(Ethylene Oxide) as Preliminary Investigation of Lithium Polymer Conductivity

2014 ◽  
Vol 893 ◽  
pp. 790-793
Author(s):  
Muhammad Naufal Lintangpradipto ◽  
Triati Dewi Kencana Wungu ◽  
Ahmad H. Lubis ◽  
Hermawan Kresno Dipojono ◽  
Nugraha
Keyword(s):  
Density Functional Theory ◽  
Ethylene Oxide ◽  
Potential Energy ◽  
Density Functional ◽  
Preliminary Investigation ◽  
Energy Curve ◽  
Functional Theory ◽  
Poly Ethylene Oxide ◽  
Poly Ethylene ◽  
Good Agreement

In this study, the interactions between poly (ethylene oxide) (PEO) and lithium-montmorillonite (LiMMT) have been investigated using density functional theory (DFT) calculation. The results of calculations show that the adsorption process of PEO on the LiMMT surface is physisorption with adsorption energy of -0.063 eV. This observation is consistent with the results of our calculations on PES (Potential Energy Surface) and PEC (Potential Energy Curve). The formation of space between PEO and LiMMT are found in range of 3.4 - 4.2 Å which are in good agreement with experimental results.

scholarly journals N-[4-(4-Chlorobenzenesulfonamido)phenylsulfonyl]acetamide

2012 ◽  
Vol 68 (6) ◽  
pp. o1913-o1913
Author(s):  
Islam Ullah Khan ◽  
Ejaz ◽  
Sidra Farid ◽  
William T. A. Harrison
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Benzene Ring ◽  
Title Compound ◽  
Dihedral Angles ◽  
Torsion Angles ◽  
Compound C ◽  
Acetyl Group

In the title compound, C14H13ClN2O5S2, the dihedral angles between the central benzene ring and the pendant chlorobenzene ring and the N-acetyl group are 82.35 (5) and 79.71 (6)°, respectively, and the overall conformation of the molecule approximates to a U shape. Both the C—S—N—C conformations are gauche, but with opposite senses [torsion angles = −59.29 (15) and 63.68 (16)°]. An intramolecular C—H...O interaction generates an S(6) ring. In the crystal, inversion dimers linked by pairs of N—H...O hydrogen bonds generate R 2 2(20) loops. A second N—H...O hydrogen bond links the dimers into (101) layers.

Structural and energy insights on solid-state complexes with trimethoprim: a combined theoretical and experimental investigation

2015 ◽  
Vol 71 (4) ◽  
pp. 406-415
Author(s):  
Anaelle Tilborg ◽  
Andrea Carletta ◽  
Johan Wouters
Keyword(s):  
Organic Salt ◽  
X Ray Diffraction ◽  
Torsion Angles ◽  
Conformational Studies ◽  
X Ray ◽  
Hydrogen Bond Interactions ◽  
Structural Database ◽  
Theoretical Results ◽  
Insight Into ◽  
Good Agreement

We present here a new structure of a 1:1 salt of trimethoprim with hemifumarate, highlighted by single-crystal X-ray diffraction and computational conformational studies. This salt was formed during cocrystallization assays conducted to combine trimethoprim and other APIs whose combination exhibits interesting properties. Theoreticalin vacuoinvestigations have been performed on the organic salt through a DFT two-dimensional conformational scan of torsion angles between the two aromatic moieties of trimethoprim. The evaluation of relative energies for hydrogen-bond interactions in the structure has also been performed. Comparison with conformational data from structures implying trimethoprim retrieved from the Cambridge Structural Database (CSD) shows good agreement with theoretical results, proving the validity of vacuumab initiocalculations in describing the energetic landscape of the molecule and thereby gain initial insight into the prediction process for possible new conformations and therefore potential new polymorphs.

Substituent effects on the chemical shifts of the bridge protons of benzonorbornenes

1967 ◽  
Vol 45 (11) ◽  
pp. 1185-1193 ◽  
Author(s):  
Naoki Inamoto ◽  
Shozo Masuda ◽  
Kazuo Tori ◽  
Katsutoshi Aono ◽  
Hiroshi Tanida
Keyword(s):  
Benzene Ring ◽  
Chemical Shifts ◽  
Substituent Effects ◽  
Electron System ◽  
Electronic Interaction ◽  
Orbital System ◽  
Significant Difference ◽  
Bridge Carbon ◽  
Hammett Relationship ◽  
Good Agreement

The substituent effects on the chemical shifts of the C9 bridge protons in a series of 6-substituted benzonorbornenes and benzonorbornadienes, and on those of the C2 protons in 5-substituted 2-indanols, were investigated. They were linearly correlated with the modified Hammett relationship τR − τH = ρ (σm + σp)/2. The ρ values obtained from the anti-C9 protons in the bornenes and bornadienes were slightly but significantly larger than those from the corresponding syn protons, whereas no significant difference was observed between the ρ values obtained from syn-9-benzonorbornenols and the indanols. The larger ρanti values were explained in terms of a stereospecific electronic interaction between the π-electron system of the benzene ring and the orbital system of the bridge carbon. In addition, it was shown that the above modified Hammett relationship gives generally a good agreement with the substituent effects on the aliphatic constituents of benzocyclenes and analogous compounds.

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