Molecular structure of para-substituted 3-aryl-2-arylmethylene-3-oxopropanenitriles in solution phase

1985 ◽  
Vol 50 (9) ◽  
pp. 1935-1947 ◽  
Author(s):  
Štefan Marchalín ◽  
Václav Jehlička ◽  
Stanislav Böhm ◽  
Petr Trška ◽  
Josef Kuthan
Keyword(s):  
Molecular Structure ◽  
Dipole Moment ◽  
Knoevenagel Condensation ◽  
Dipole Moments ◽  
Solution Phase ◽  
Conformational Structure ◽  
Spectral Measurements ◽  
Electrical Dipole ◽  
Dipolar Structure ◽  
C Nmr

The conformational structure of the title compounds has been investigated by application of EHT calculations, 1H and 13C NMR spectral measurements, and calculated/found electrical dipole moments. It has been proved that compounds Ia-Ie and IIa-IIf obtained by thermodynamically-controlled Knoevenagel condensation are all E isomers. The dipole moment of compound Ia indicates a partially dipolar structure.

scholarly journals Dipole moments and molecular structure. Part I.— A simple resonance method for the measurement of dielectric constants

1932 ◽  
Vol 136 (829) ◽  
pp. 251-255 ◽  
Keyword(s):  
Molecular Structure ◽  
Dipole Moment ◽  
Dipole Moments ◽  
Resonance Method ◽  
Dielectric Constants ◽  
Present Communication ◽  
Dilute Solutions ◽  
Resonance Circuit ◽  
Low Resistance ◽  
Voltage Resonance

Numerous types of resonance methods for the measurement of dielectric constants have been described by different investigators. That detailed in the present communication has no claim to originality, but it is a simple, whilst at the same time reliable, form, which has proved to be very useful for the measurement of the dielectric constants of dilute solutions for the purpose of dipole moment determination. A fairly powerful oscillator is used, enabling the valveless resonance circuit to be some distance removed from it, whilst still receiving ample “pick-up” for the measurements. Resonance in the pick-up circuit is detected by means of a low-resistance thermo-junction, introduced directly into the circuit. The resistance thus introduced does not damp the oscillation unduly. The very small conductivity of the solvent liquids employed does not produce any appreciable error owing to the current resonance not occurring at the same tuning capacity as the voltage resonance.

Determination of dipole moment values of anisotropic molecules using Brot's formalism

1990 ◽  
Vol 68 (9) ◽  
pp. 1523-1526
Author(s):  
P. Brito ◽  
M. Mechetti
Keyword(s):  
Molecular Structure ◽  
Dipole Moment ◽  
Dipole Moments ◽  
Dilute Solutions ◽  
Molecular Anisotropy ◽  
Derivatives Of ◽  
Best Parameters

A method for the determination of dipole moment values based on Brot's theory is proposed. It takes into account the influence of the molecular anisotropies of shape and polarizability on the permittivity of a mixture. Starting from measurements performed on dilute solutions and from the knowledge of the molecular structure of some chlorinated derivatives of α-cyanostilbene and 1,3 derivatives of benzene, the best parameters of an ellipsoid used for the representation of a polar anisotropic molecule are determined. The dipole moments obtained, using benzene and tetrachloromethane as solvents, are finally compared to values from the literature. Keywords: dipole moment, Brot's formalism, molecular anisotropy.

Three-membered Rings. Molecular Structure and Conformation of Aryl Substituted Oxiranes by Dipole Moment Measurements

1977 ◽  
Vol 32 (12) ◽  
pp. 1467-1472 ◽  
Author(s):  
Salvatore Sorriso ◽  
Carlo Battistini ◽  
Bruno Macchia ◽  
Franco Macchia
Keyword(s):  
Molecular Structure ◽  
Dipole Moment ◽  
Electric Dipole ◽  
Dipole Moments ◽  
Phenyl Group ◽  
Electric Dipole Moments ◽  
Bond Angles ◽  
Styrene Derivatives

The electric dipole moments of some styrene and trans- and cis-stilbene oxides have been measured, in benzene. From these data some bond angles have been calculated and it has been deduced that in the styrene derivatives the phenyl group is in rapid interconversion about the bond with the triatomic ring.

On the conformational structure of nicotinamide and methyl-1,4-dihydronicotinamide

1979 ◽  
Vol 44 (9) ◽  
pp. 2633-2638 ◽  
Author(s):  
Hans-Jörg Hofmann ◽  
Josef Kuthan
Keyword(s):  
Molecular Structure ◽  
Continuum Model ◽  
Model Analysis ◽  
Wave Functions ◽  
Conformational Structure ◽  
Influence Of Solvent

The conformation of nicotinamide (I) and 1-methyl-1,4-dihydronicotinamide (II) was examined using the NDDO method. The influence of solvent on the molecular structure of the title compounds was estimated by means of a continuum model. Analysis of the NDDO wave functions contributes to the knowledge about the mechanism of the NADH reduction.

Conformational structure of ethylene glycol dibenzoate. Vibrational and NMR spectra

1981 ◽  
Vol 46 (8) ◽  
pp. 1913-1929 ◽  
Author(s):  
Bohdan Schneider ◽  
Pavel Sedláček ◽  
Jan Štokr ◽  
Danica Doskočilová ◽  
Jan Lövy
Keyword(s):  
Ethylene Glycol ◽  
Vibrational Spectra ◽  
Nmr Spectra ◽  
Coupling Constants ◽  
Conformational Structure ◽  
Infrared And Raman Spectra ◽  
H Nmr ◽  
Liquid States ◽  
Crystalline Forms ◽  
C Nmr

It was found that three crystalline forms of ethylene glycol dibenzoate can be prepared. Infrared and Raman spectra of these three forms, as well as of the glassy and liquid states, were measured. From 3JHH coupling constants obtained by analysis of the 13C satellite band of the -CH2- group in 1H NMR spectra, and from the 3JCH coupling constants of the -CO.O.CH2- fragment obtained by analysis of the carbonyl band in 13C NMR spectra it was found that in the liquid state the -CH2-CH2- group exists predominantly in the gauche conformational structure, and the bonds C-O-C-C assume predominantly a trans orientation. The results of the analysis of NMR and vibrational spectra were used for the structural interpretation of conformationally sensitive bands in vibrational spectra of ethylene glycol dibenzoate.

Energies and Electric Dipole Moments of the Bound Vibrational States of HN2+ and DN2+

2008 ◽  
Vol 73 (6-7) ◽  
pp. 873-897 ◽  
Author(s):  
Vladimír Špirko ◽  
Ota Bludský ◽  
Wolfgang P. Kraemer
Keyword(s):  
Dipole Moment ◽  
Nearest Neighbor ◽  
Energy Surface ◽  
Dipole Moments ◽  
Three Dimensional ◽  
Vibrational States ◽  
Spacing Distribution ◽  
Triatomic Molecules ◽  
Vibrational Levels ◽  
Different Levels

The adiabatic three-dimensional potential energy surface and the corresponding dipole moment surface describing the ground electronic state of HN2+ (Χ1Σ+) are calculated at different levels of ab initio theory. The calculations cover the entire bound part of the potential up to its lowest dissociation channel including the isomerization barrier. Energies of all bound vibrational and low-lying ro-vibrational levels are determined in a fully variational procedure using the Suttcliffe-Tennyson Hamiltonian for triatomic molecules. They are in close agreement with the available experimental numbers. From the dipole moment function effective dipoles and transition moments are obtained for all the calculated vibrational and ro-vibrational states. Statistical tools such as the density of states or the nearest-neighbor level spacing distribution (NNSD) are applied to describe and analyse general patterns and characteristics of the energy and dipole results calculated for the massively large number of states of the strongly bound HN2+ ion and its deuterated isotopomer.

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