Solvation Dynamics of a Radical Ion Pair in Micro-Heterogeneous Binary Solvents: A Semi-Quantitative Study Utilizing MARY Line-Broadening Experiments

ChemPhysChem ◽  
2013 ◽  
Vol 14 (14) ◽  
pp. 3389-3399 ◽  
Author(s):  
Kunal Pal ◽  
Günter Grampp ◽  
Daniel R. Kattnig
Keyword(s):  
Quantitative Study ◽  
Ion Pair ◽  
Binary Solvents ◽  
Solvation Dynamics ◽  
Line Broadening

Ion pair and solvation dynamics of [Bmim][BF4 ] + water system

2017 ◽  
Vol 56 (2) ◽  
pp. 127-139 ◽  
Author(s):  
João Cascão ◽  
Wagner Silva ◽  
Ana S.D. Ferreira ◽  
Eurico J. Cabrita
Keyword(s):  
Water System ◽  
Ion Pair ◽  
Solvation Dynamics

scholarly journals Microsolvation and sp2-stereoinversion of monomeric α-(2,6-di-tert-butylphenyl)vinyllithium as measured by NMR

2014 ◽  
Vol 10 ◽  
pp. 2521-2530 ◽  
Author(s):  
Rudolf Knorr ◽  
Monika Knittl ◽  
Eva C Rossmann
Keyword(s):  
Title Compound ◽  
Low Temperatures ◽  
Ion Pair ◽  
Coupling Constants ◽  
Ionic Mechanism ◽  
Line Broadening ◽  
Aryl Group ◽  
H Nmr ◽  
Nmr Signals ◽  
Butyl Methyl Ether

The β-unsubstituted title compound dissolves in THF as a uniformly trisolvated monomer, whereas it forms exclusively disolvated monomers in tert-butyl methyl ether, Et2O, TMEDA, or toluene with TMEDA (1.4 equiv). This was established at low temperatures through the observation of separated NMR signals for free and lithium-coordinated ligands and/or through the patterns and magnitudes of 13C,6Li NMR coupling constants. An aggregated form was observed only with Et2O (2 equiv) in toluene as the solvent. The olefinic geminal interproton coupling constants of the H2C= part can be used as a secondary criterion to differentiate between these differently solvated ground-states (3, 2, or <2 coordinated ligands per Li). Due to a kinetic trisolvation privilege of THF, the cis/trans sp2-stereoinversion rates could be measured through analyses of 1H NMR line broadening and coalescence only in THF as the solvent: The pseudomonomolecular (because THF-catalyzed), ionic mechanism is initialized by a C–Li bond heterolysis with the transient immobilization of one additional THF ligand, followed by stereoinversion of the quasi-sp2-hybridized carbanionic center in cooperation with a “conducted tour” migration of Li+(THF)4 along the α-aryl group within the solvent-separated ion pair.

Study of the exchange rates of ethanol and water on ferriprotoporphyrin IX by n.m.r. line broadening

1969 ◽  
Vol 47 (17) ◽  
pp. 3217-3224 ◽  
Author(s):  
N. S. Angerman ◽  
B. B. Hasinoff ◽  
H. B. Dunford ◽  
R. B. Jordan
Keyword(s):  
Exchange Rates ◽  
Temperature Jump ◽  
Aqueous Ethanol ◽  
Ion Pair ◽  
Solvent Composition ◽  
Water Proton ◽  
Solvent Exchange ◽  
Line Broadening ◽  
Kcal Mole ◽  
Ethanol Molecule

The nuclear magnetic resonance (n.m.r.) line broadening technique has been used to determine the rate of solvent exchange from the first coordination sphere of ferriprotoporphyrin IX (hemin) in aqueous ethanol. The line broadenings of the methyl and methylene protons of ethanol and the water protons have been studied as a function of solvent composition at 35° and of temperature in 48.8 mole % ethanol.The average values of the kinetic parameters for ethanol molecule exchange, taken from the CH3 and CH2 proton broadening are ΔH≠ = 6.2 ± 1.0 kcal mole−1 and ΔS≠ = −9.1 ± 4.4 cal mole−1 deg−1. Both proton transfer and water molecule exchange contribute to the water proton line broadening with a net value of ΔH≠ = 6.3 ± 0.5 kcal mole−1 and ΔS≠ = −3.8 ± 2.0 cal mole−1 deg−1.From the n.m.r. study at varying solvent composition, it is concluded that monomeric and dimeric hemin undergo solvent exchange at the same rate. The equilibrium constant for formation of the monoethanol solvated hemin from hydroxyhemin is determined as 8.7 at 35° from this study.A comparison of the rate of ethanol exchange (1.8 × 106 s−1 at 25°) and the rate of imidazole binding to hemin (from a separate temperature jump study) indicates that the imidazole substitution occurs through an SN1 ion pair mechanism.

Anioneneinflüsse auf die Elektronenspinresonanz von Mangan(II)salzen in wäßriger Lösung

1969 ◽  
Vol 24 (4) ◽  
pp. 573-577 ◽  
Author(s):  
P. Nehmiz ◽  
M. Stockhausen
Keyword(s):  
Room Temperature ◽  
Ion Pairs ◽  
Ion Pair ◽  
Pair Formation ◽  
Line Broadening ◽  
Salt Solutions ◽  
Ion Pair Formation ◽  
Short Lifetime ◽  
Long Lifetime ◽  
The Mean

Abstract The mean esr linewidth of hfs components of aqueous mangenese salt solutions has been measured a t 9 GHz and room temperature from small to medium concentrations, also with added diamagnetic salts. In all cases the linewidth depends on the viscosity of the solutions. Further, already at very small concentrations a specific anion dependend line broadening has been observed, evidently resulting from ion pair formation. Roughly spoken, in the whole concentration range two anion families exist. Nitrate and halides show smaller line broadening, they form ion pairs with long lifetime. Sulfate, acetate and formiate show larger line broadening; they form ion pairs with short lifetime.

Ion Association and Solvation in Dichloromethane of Tetrachloro-and Tetrabromoferrates(III) Compared with Simple Halides

1978 ◽  
Vol 33 (7) ◽  
pp. 745-749 ◽  
Author(s):  
S. Bait ◽  
G. du Chattel ◽  
W. de Kieviet ◽  
A. Tieleman
Keyword(s):  
Hydrogen Bonds ◽  
Ion Association ◽  
Ion Pair ◽  
Association Constants ◽  
Halide Ions ◽  
Conductivity Measurements ◽  
Line Broadening ◽  
Experimental Values

Abstract Conductivity measurements are reported in dichloromethane for tetraethylammonium and tetraphenylarsonium salts of tetrachloro-and tetrabromoferrate(III) and halide ions (chiefly chloride and bromide). Analysis of the data in terms of the recent Fuoss equation has given the ion-pair association constants. The experimental values are close to the ones calculated from the electrostatic Fuoss-Eigen equation. The solvent acts as an acceptor by way of forming hydrogen-bonds to the simple halide ions and to a much less extent to the ferrates. Solvation of chloro-and bromoferrates(III) seems to be comparable, as deduced from the association constants and NMR paramagnetic line broadening. The phenyl groups of the tetraphenylarsonium ion seem to give π-interaction with the solvent.

Electron-Mirror Microscopic Aspects of Ferroelectric Domains of BaTiO3 And Ca2Sr (C2H5CO2)6

1970 ◽  
Vol 28 ◽  
pp. 478-479
Author(s):  
Teruo Someya ◽  
Jinzo Kobayashi
Keyword(s):  
Surface Layer ◽  
Electric Fields ◽  
Quantitative Study ◽  
Recent Progress ◽  
Ferroelectric Domain ◽  
Resolving Power ◽  
Surface Pattern ◽  
Crystal Surfaces ◽  
One Dimensional ◽  
Ferroelectric Domains

Recent progress in the electron-mirror microscopy (EMM), e.g., an improvement of its resolving power together with an increase of the magnification makes it useful for investigating the ferroelectric domain physics. English has recently observed the domain texture in the surface layer of BaTiO3. The present authors ) have developed a theory by which one can evaluate small one-dimensional electric fields and/or topographic step heights in the crystal surfaces from their EMM pictures. This theory was applied to a quantitative study of the surface pattern of BaTiO3).

A Quantitative Study of the Gastric Secretory Response to Sham Feeding in a Human Subject

1950 ◽  
Vol 16 (1) ◽  
pp. 104-116 ◽  
Author(s):  
Henry D. Janowitz ◽  
Franklin Hollander ◽  
David Orringer ◽  
Milton H. Levy ◽  
Asher Winkelstein ◽  
...  
Keyword(s):  
Quantitative Study ◽  
Human Subject ◽  
Secretory Response ◽  
Sham Feeding
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