Studies of complex formation from permittivity measurements: a statistical reexamination

1992 ◽  
Vol 70 (7) ◽  
pp. 1873-1878 ◽  
Author(s):  
Otto Exner
Keyword(s):  
Dipole Moment ◽  
Complex Formation ◽  
Classical Method ◽  
Dipole Moments ◽  
Equilibrium Constants ◽  
Statistical Treatment ◽  
Statistical Procedure ◽  
Variable Ratio ◽  
Transformation Of Variables ◽  
Permittivity Measurements

Permittivity measurements on solutions of two compounds present in a variable ratio may reveal complex formation: both the equilibrium constant and the dipole moment of the complex can be in principle estimated. However, an incorrect statistical treatment involving transformation of variables is used quite often, for example, in the classical method of Few and Smith. In this case the estimates obtained are usually biased, or loaded with such a great uncertainty that they are practically worthless. The results of numerous papers, even some recent ones, are thus completely at variance with facts. This is shown in this paper by recalculating equilibrium constants and dipole moments of the complex in 17 examples from the literature. Simultaneously, a correct and simple statistical procedure is suggested. The danger of an incorrect and (or) incomplete statistical treatment may be encountered, for the same reason, even in other, quite different, areas.

Dipole moments of some aromatic and aliphatic aldehydes. Their dependence on the solvent and the atomic polarization

1985 ◽  
Vol 63 (5) ◽  
pp. 1031-1034 ◽  
Author(s):  
Constantino Grosse ◽  
Magdalena Mechetti ◽  
Pedro Brito
Keyword(s):  
Dipole Moment ◽  
Solvent Effect ◽  
Dipole Moments ◽  
Electronic Polarization ◽  
Atomic Polarization ◽  
Aliphatic Aldehydes ◽  
Permittivity Measurements

The dipole moments of 21 aromatic and aliphatic aldehydes were determined. Permittivity measurements were performed on highly diluted cyclohexane solutions at 20 °C. The limiting forms of Debye's, Onsager's, and Bordewijk's expressions were used. The influence of the solvent on the dipole moment values was studied using decalin and heptane mixtures. Only the Debye's values presented an apparent solvent effect while the Onsager's and Bordewijk's values remained independent of the solvent. Dipole moment values obtained using the refractive indexes of the components were also compared with those derived using the refractive indexes of the mixtures. This permitted one to estimate in 0.07 the relation between atomic and electronic polarization.

Etude de l'équilibre dans les oxazolo[2,3-e], thiazolo[2,3-e] et isoxazolo[2,3-d]tétrazoles. II. Etude de l'effet de la température par dipolemetrie et résonance magnétique nucléaire

1977 ◽  
Vol 55 (10) ◽  
pp. 1728-1735 ◽  
Author(s):  
Robert Faure ◽  
Jean-Pierre Galy ◽  
Emile-Jean Vincent ◽  
Jean-Pierre Fayet ◽  
Pierre Mauret ◽  
...  
Keyword(s):  
Dipole Moment ◽  
Equilibrium Constant ◽  
Dipole Moments ◽  
Equilibrium Constants ◽  
Proton Nmr ◽  
Photoelectron Spectra ◽  
A Value ◽  
Résonance Magnétique ◽  
Entropy Factor

The equilibrium constant in dioxane between azido and tétrazole isomers has been obtained for five heterocyclic azides (2-azido thiazoles, benzothiazole, benzoxazole, and 3-azido isoxazole) by proton nmr and dipole moment- studies. The last method involves a comparison between experimental and calculated (INDO, CNDO/2, CNDO/S) dipole moments. The CNDO/S method gives the best equilibrium constants and entropy factor (ΔS ∼ 50 J K−1 mol−1). A value of 114° for the C—N—N angle is found to account satisfactorily for certain properties (energy, dipole moment, photoelectron spectra) of aromatic azides. The heterocyclic azidoimines prefer the Z conformation.

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.

scholarly journals Cooperation/Competition between Halogen Bonds and Hydrogen Bonds in Complexes of 2,6-Diaminopyridines and X-CY3 (X = Cl, Br; Y = H, F)

Symmetry ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 766
Author(s):  
Barbara Bankiewicz ◽  
Marcin Palusiak
Keyword(s):  
Complex Formation ◽  
Hydrogen Bonds ◽  
Dft Calculations ◽  
Electrostatic Interactions ◽  
Dipole Moments ◽  
Main Role ◽  
Halogen Bonds ◽  
Topological Parameters ◽  
Leading Role ◽  
The Impact

The DFT calculations have been performed on a series of two-element complexes formed by substituted 2,6-diaminopyridine (R−PDA) and pyridine (R−Pyr) with X−CY3 molecules (where X = Cl, Br and Y = H, F). The primary aim of this study was to examine the intermolecular hydrogen and halogen bonds in the condition of their mutual coexistence. Symmetry/antisymmetry of the interrelation between three individual interactions is addressed. It appears that halogen bonds play the main role in the stabilization of the structures of the selected systems. However, the occurrence of one or two hydrogen bonds was associated with the favourable geometry of the complexes. Moreover, the impact of different substituent groups attached in the para position to the aromatic ring of the 2,6-diaminopyridine and pyridine on the character of the intermolecular hydrogen and halogen bonds was examined. The results indicate that the presence of electron-donating substituents strengthens the bonds. In turn, the presence of electron-withdrawing substituents reduces the strength of halogen bonds. Additionally, when hydrogen and halogen bonds lose their leading role in the complex formation, the nonspecific electrostatic interactions between dipole moments take their place. Analysis was based on geometric, energetic, and topological parameters of the studied systems.

scholarly journals DERIVATION OF GENERALIZED THOMAS–BARGMANN–MICHEL–TELEGDI EQUATION FOR A PARTICLE WITH ELECTRIC DIPOLE MOMENT

2013 ◽  
Vol 28 (29) ◽  
pp. 1350147 ◽  
Author(s):  
TAKESHI FUKUYAMA ◽  
ALEXANDER J. SILENKO
Keyword(s):  
Dipole Moment ◽  
Electromagnetic Fields ◽  
Electric Dipole Moment ◽  
Electric Dipole ◽  
Dipole Moments ◽  
Classical Equation ◽  
Spin Motion ◽  
Electric Dipole Moments ◽  
Momentum Direction ◽  
Telegdi Equation

General classical equation of spin motion is explicitly derived for a particle with magnetic and electric dipole moments in electromagnetic fields. Equation describing the spin motion relative to the momentum direction in storage rings is also obtained.

Dipole moment and molecular structure. Part XVII. The dipole moments of azo-dyes and some similar substances

1936 ◽  
Vol 32 ◽  
pp. 1318 ◽  
Author(s):  
Ernst Bergmann ◽  
Anna Weizmann
Keyword(s):  
Molecular Structure ◽  
Dipole Moment ◽  
Azo Dyes ◽  
Dipole Moments

Charge-Transfer Dipoles at the Si-SiO2 Interface and the Metal-Semiconductor Worfunction Difference In Mos Devices.

1987 ◽  
Vol 105 ◽  
Author(s):  
Hisham Z. Massoud
Keyword(s):  
Dipole Moment ◽  
Charge Transfer ◽  
Dipole Moments ◽  
Silicon Substrates ◽  
Interface Dipole ◽  
Mos Devices ◽  
Flatband Voltage ◽  
The Difference ◽  
Definition Of ◽  
Mos Structures

AbstractThe magnitude of the dipole moment at the Si-SiO2 interface resulting from partial charge transfer that takes place upon the formation of interface bonds has been calculated. The charge transfer occurs because of the difference in electronegativity between silicon atoms and SiO2 molecules which are present across the interface. Results obtained for (100) and (111) silicon substrates indicate that the magnitude of the interface dipole moment is dependent on substrate orientation and the interface chemistry. Dipole moments at the Si-SiO2 and gate-SiO2 interfaces should be included in the definition of the flatband voltage VFB of MOS structures. CV-based measurements of the metal-semiconductor workfunction difference φms on (100) and (111) silicon oxidized in dry oxygen and metallized with Al agree with the predictions of this model. Other types of interface dipoles and their processing dependence are briefly discussed.

Experimental and computed dipole moments in donor–bridge–acceptor systems with p-phenylene and p-carboranediyl bridges

2009 ◽  
Vol 74 (1) ◽  
pp. 131-146 ◽  
Author(s):  
Ladislav Drož ◽  
Mark A. Fox ◽  
Drahomír Hnyk ◽  
Paul J. Low ◽  
J. A. Hugh MacBride ◽  
...  
Keyword(s):  
Dipole Moment ◽  
Dipole Moments ◽  
Electronic Effects ◽  
Electronic Interactions ◽  
Donor And Acceptor ◽  
Homo And Lumo ◽  
Pull Systems ◽  
The Difference ◽  
Experimental Values ◽  
2D And 3D

Dipole moments were measured for a series of substituted benzenes, biphenyls, terphenyls, C-monoaryl- and C,C′-diaryl-p-carboranes. For the donor–bridge–acceptor systems, Me2N–X–NO2, where X is 1,4-phenylene, biphenyl-4,4′-diyl, terphenyl and 1,4-C6H4-p-CB10H10C-1,4-C6H4, the measured interaction dipole moments are 1.36, 0.74, 0.51 and 0.00 D, respectively. The magnitude of the dipole moment reflects the ability of the bridge to transmit electronic effects between donor and acceptor groups. Thus, whilst the 1,4-phenylene bridges allow moderate electronic interactions between the remote groups, the p-carboranediyl unit is less efficient as a conduit for electronic effects. Averaged dipole moments computed at the DFT (B3LYP/6-31G*) level of theory from two distinct molecular conformers are in good agreement with the experimental values. Examination of the calculated electronic structures provides insight into the nature of the interactions between the donor and acceptor moieties through these 2D and 3D aromatic bridges. The most significant cooperative effect of the bridge on the dipole moment occurs in systems where there is some overlap between the HOMO and LUMO orbitals. This orbital overlap criterion may help to define the difference between “push-pull” systems in which electronic effects are mediated by the bridging moiety, and simpler systems in which the bridge acts as an electronically innocent spacer unit and through-space charge transfer/separation is dominant.

Ionic dissociation in complexes of iodine with triphenylarsine and triphenylstibine

1991 ◽  
Vol 69 (4) ◽  
pp. 606-610 ◽  
Author(s):  
Ying Ru Zhang ◽  
Ira Solomon ◽  
Seymour Aronson
Keyword(s):  
Complex Formation ◽  
Chemical Nature ◽  
Equilibrium Constants ◽  
Electrochemical Technique ◽  
High Iodine ◽  
Ionic Complex ◽  
Ionization Mechanisms ◽  
Iodine Complex ◽  
Ionic Dissociation ◽  
Iodine Complexes

An electrochemical technique has been employed to study the ionization of the iodine complexes of (C6H5)3As, (C6H5)3Sb, and pyridine. Several different ionization mechanisms are proposed depending on the chemical nature and concentration of the reactants. A new ionic complex, (C6H5)3MI22+ is postulated for the interaction of iodine with (C6H5)3As and (C6H5)3Sb at high iodine concentrations. Equilibrium constants have been calculated from the emf data for the various ionization steps. Key words: triphenylarsine, triphenylstibine, iodine, complex formation, ionization.

HQC with the AC setup associated with topological defects

2011 ◽  
Vol 11 (5&6) ◽  
pp. 444-455
Author(s):  
Knut Bakke ◽  
Cláudio Furtado
Keyword(s):  
Dipole Moment ◽  
Electric Field ◽  
Magnetic Dipole ◽  
Magnetic Dipole Moment ◽  
Topological Defect ◽  
Dipole Moments ◽  
Topological Defects ◽  
Quantum Phases ◽  
Neutral Particles ◽  
New Formulation

In this work, we propose a new formulation allowing to realize the holonomic quantum computation with neutral particles with a permanent magnetic dipole moments interacting with an external electric field in the presence of a topological defect. We show that both the interaction of the electric field with the magnetic dipole moment and the presence of topological defect generate independent contributions to the geometric quantum phases which can be used to describe any arbitrary rotation on the magnetic dipole moment without using the adiabatic approximation.

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