Study of chiroptical properties of some piperidine derivatives

1983 ◽  
Vol 48 (6) ◽  
pp. 1624-1634
Author(s):  
Otakar Červinka ◽  
Anna Fábryová ◽  
Vladimír Šňupárek ◽  
František Strejček
Keyword(s):  
Wave Function ◽  
Chiroptical Properties ◽  
Cd Spectrum ◽  
Chemical Correlation ◽  
The Individual ◽  
Theory And Experiment

Chiroptical properties of (S)-(-)-1-methyl-2-phenylpiperidine and (S)-(-)-1-methyl-2-(2-tolyl)piperidine have been studied. The preferred conformations have been calculated in gradient way on the basis of the CNDO/2 method, and the rotational forces have been calculated for them by direct procedure using the CNDO/S-CI wave function. For comparison of theory and experiment, molar fractions of the individual conformers have been calculated and used together with the rotational forces for construction of the CD spectrum which has been compared with the experimental CD spectrum. Absolute configurations of the mentioned compounds have been determined by chemical correlation.

Chiroptical properties of pyrrolidine derivatives

1983 ◽  
Vol 48 (6) ◽  
pp. 1618-1623
Author(s):  
Otakar Červinka ◽  
Ilja Sedlák ◽  
František Strejček
Keyword(s):  
Wave Function ◽  
Absolute Configuration ◽  
Molecular Geometry ◽  
Cd Spectra ◽  
Chiroptical Properties ◽  
Total Gradient ◽  
Gradient Optimization ◽  
Chemical Correlation ◽  
Rotational Strengths

CD spectra of (S)-(-)-2-phenyl-1-methylpyrrolidine (I) and (S)-(-)-1-methyl-2-(2-tolyl)pyrrolidine (II) were calculated. Rotational strengths were calculated by direct procedure based on the CNDO/S-CI wave function. The most stable conformations were determined by total gradient optimization of molecular geometry and their molar fractions were calculated. CD spectra, constructed from the molar fractions and rotational strengths, agreed well with the experimental ones. Absolute configuration of compound II was established by the chemical correlation with (S)-(-)-hygrinic acid.

scholarly journals Extracting Interface Correlations from the Pair Distribution Function of Composite Materials

2021 ◽  
Author(s):  
Harry Geddes ◽  
Henry D. Hutchinson ◽  
Alex R Ha ◽  
Nicholas P. Funnell ◽  
Andrew Goodwin
Keyword(s):  
Distribution Function ◽  
Pair Distribution Function ◽  
Functional Materials ◽  
Model System ◽  
Complex Mixtures ◽  
Proof Of Concept ◽  
X Ray ◽  
The Individual ◽  
Theory And Experiment ◽  
Matrix Factorisation

<div> <div> <div> <p>Using a non-negative matrix factorisation (NMF) approach, we show how the pair distribution function (PDF) of complex mixtures can be deconvolved into the contributions from the individual phase components and also the interface between phases. Our focus is on the model system Fe||Fe3O4. We establish proof-of-concept using idealised PDF data generated from established theory-driven models of the Fe||Fe3O4 interface. Using X-ray PDF measurements for corroded Fe samples, and employing our newly-developed NMF analysis, we extract the experimental interface PDF (‘iPDF’) for this same system. We find excellent agreement between theory and experiment. The implications of our results in the broader context of interface characterisation for complex functional materials are discussed. </p> </div> </div> </div>

The quantum mechanical theory of environmental effects

1960 ◽  
Vol 255 (1280) ◽  
pp. 63-68 ◽  
Keyword(s):  
Wave Function ◽  
Environmental Effects ◽  
Quantum Mechanical ◽  
Mechanical Theory ◽  
Wave Mechanics ◽  
Quantum Mechanical Theory ◽  
The Individual

A basic postulate of wave mechanics is that the wave function of a microscopic system develops in time according to the equation iℏ∂ψ/∂ t = H ψ, where H , the Hamiltonian, is an operator which in general depends upon the time. If, and only if, the Hamiltonian is time-independent, then the solutions of this equation take the form ψ( q, t ) = ∑ n c n Ѱ n ( q )e -1 E n t /ℏ , (2) where the individual terms Ѱ n ( q ) are functions of the co-ordinates alone and the E n are the corresponding eigenvalues of the Hamiltonian, satisfying HѰ n = E n Ѱ n . (3)

Chiroptical Properties of Streptorubin B: The Synergy Between Theory and Experiment

Chirality ◽  
2015 ◽  
Vol 27 (10) ◽  
pp. 745-751 ◽  
Author(s):  
Marta S. Andrade ◽  
Vanessa S. Silva ◽  
Ana M. Lourenço ◽  
Ana M. Lobo ◽  
Henry S. Rzepa
Keyword(s):  
Chiroptical Properties ◽  
Theory And Experiment

Study of Single Crystals of Magnesium and Zinc by Positron Annihilation

1972 ◽  
Vol 50 (20) ◽  
pp. 2520-2522 ◽  
Author(s):  
E. H. Becker ◽  
E. M. D. Senicki ◽  
A. G. Gould ◽  
B. G. Hogg
Keyword(s):  
Wave Function ◽  
Single Crystals ◽  
Positron Annihilation ◽  
Enhancement Factor ◽  
Wave Functions ◽  
Theoretical Predictions ◽  
Positron Wave Function ◽  
Electronic Wave Functions ◽  
Simple Picture ◽  
Theory And Experiment

A point geometry positron annihilation angular correlation apparatus has been used to study oriented single crystals of magnesium and zinc. The results are compared with the theoretical predictions obtained from a simple picture of the electronic wave functions combined with two models for the positron wave function. The agreement between theory and experiment is considerably improved in the case of magnesium by the use of an enhancement factor.

scholarly journals Resolution of P-Sterogenic 1-Phenylphosphin-2-en-4-one 1-Oxide into Two Enantiomers by (R,R)-TADDOL and Conformational Diversity of the Phosphinenone Ring and TADDOL in the Crystal State

Molecules ◽  
2021 ◽  
Vol 26 (22) ◽  
pp. 6873
Author(s):  
Elżbieta Łastawiecka ◽  
Adam Włodarczyk ◽  
Anna E. Kozioł ◽  
Hanna Małuszyńska ◽  
Kazimierz Michał Pietrusiewicz
Keyword(s):  
Structural Analysis ◽  
Conformational Changes ◽  
Flash Chromatography ◽  
Ligand Molecule ◽  
X Ray Crystallography ◽  
Conformational Diversity ◽  
Chemical Correlation ◽  
The Absolute ◽  
The Individual ◽  
Diastereomeric Complexes

The resolution of racemic 1-phenylphosphin-2-en-4-one 1-oxide (2), was achieved through the fractional crystallization of its diastereomeric complexes with (4R,5R)-(−)-2,2-dimethyl -α,α,α′,α′-tetraphenyl-dioxolan-4,5-dimethanol (R,R-TADDOL) followed by the liberation of the individual enantiomers of 2 by flash chromatography on silica gel columns. The resolution process furnished the two enantiomers of 2 of 99.1 and 99.9% e.e. at isolated yields of 62 and 59% (counted for the single enantiomer), respectively. The absolute configurations of the two enantiomers were established by means of X-ray crystallography of their diastereomerically pure complexes, i.e., (R)-2•R,R)-TADDOL and (S)-2•(R,R)-TADDOL. The structural analysis revealed that in the (R)-2•(R,R)-TADDOL complex, the P-phenyl substituent occupied a pseudoequatorial position, whereas in (S)-2•(R,R)-TADDOL, it appeared in both the pseudoequatorial and the pseudoaxial positions in four symmetrically independent molecules. Concurrent conformational changes of the TADDOL molecules were best described by the observed changes of a pseudo-torsional CO...OC angle that could be considered as a possible measure of TADDOL conformation in its receptor–ligand complexes. The structural analysis of the (R,R)-TADDOL molecule revealed that efficiency of this compound for use as an effective resolving factor comes from its ability to flexibly fit its structure to both enantiomers of a ligand molecule, producing a rare case of resolution for both pure enantiomers with one chiral separating agent. The resolved (R)-2 was used to assign the absolute configuration of a recently described (−)-1-phenylphosphin-2-en-4-one 1-sulfide by chemical correlation. In addition, an attempted stereoretentive reduction of (R)-2 by PhSiH3 at 60 °C revealed an unexpectedly low barrier for P-inversion in 1-phenylphosphin-2-en-4-one.

Quantitative High-Resolution Transmission Electron Microscopy of III-V Semiconductor Interfaces by Multivariate Statistical Analysis of Exit-Plane Wave Function Images

2002 ◽  
Vol 727 ◽  
Author(s):  
Krishnamurthy Mahalingam ◽  
Kurt G. Eyink ◽  
Gail J. Brown ◽  
Donald L. Dorsey
Keyword(s):  
Wave Function ◽  
Plane Wave ◽  
Atomic Scale ◽  
Specimen Thickness ◽  
Exit Plane ◽  
Multivariate Statistical ◽  
Wide Range ◽  
Chemical Content ◽  
Residual Thickness ◽  
The Individual

AbstractThe application of exit-plane wave function (EPWF) images for an atomic-scale compositional mapping of interfaces in the GaAs-AlAs system is investigated. Image simulations based on the multislice algorithm were performed to obtain EPWF images over a wide range of compositions and specimen thicknesses. The EPWF-amplitude images were further analyzed by the method of factorial analysis of correspondence. A simultaneous analysis of the effects both thickness and composition on image contrast yielded two eigenvectors representing the individual contributions from the two effects. This separation was however not complete, leaving a residual contribution from thickness on the composition-sensitive eigenvector and vice versa. Extraction of the chemical content from the composition-sensitive eigenvector is still possible by a parameterization of the residual thickness contribution. A simpler procedure for quantifying the composition across an interface is proposed based on the analysis of images of AlxGa(1-x)As with different Al/Ga composition but same specimen thickness.

scholarly journals The Domain of the Quantum Matter Wave

2001 ◽  
Vol 56 (1-2) ◽  
pp. 216-219
Author(s):  
B. Mills
Keyword(s):  
Wave Function ◽  
Particle System ◽  
Physical Space ◽  
Quantum Systems ◽  
Matter Wave ◽  
Quantum Matter ◽  
Multiple Particles ◽  
Complex Wave ◽  
The Individual ◽  
Individual Particles

AbstractIn quantum mechanics a particle is represented by a complex wave function. This is similar to the classical description of a distributed particle by a real valued density function. However, while classically the combined density of multiple particles can be decomposed into individual densities; the wave function of a multi-particle system can not always be decomposed into wave functions for the individual particles. Hence the classical assumption that density is a property of physical space, which is only possible because of the special topology of classical configuration space, does not work for quantum systems.

P-V-T behaviour of hard body fluids. Theory and experiment

1986 ◽  
Vol 51 (11) ◽  
pp. 2301-2432 ◽  
Author(s):  
Tomáš Boublík ◽  
Ivo Nezbeda
Keyword(s):  
Virial Coefficients ◽  
Numerical Data ◽  
Body Fluids ◽  
Simulation Results ◽  
The Individual ◽  
Compressibility Factors ◽  
Theory And Experiment

All available numerical data on virial coefficients along with simulation results for the compressibility factors of hard body fluids and their mixtures have been compiled. Practically all relevant theories for these fluids (lattice theories, specific methods for discontinuous potentials, integral and integro-differential theories, expansion and resummation techniques, as well as perturbation and conformal theories) are reviewed and their results are compared with the data. The individual methods are critically assessed and their advantages and limits are discussed.

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