Electrophilic cleavage of cyclopropanes. III. The reaction of molecular bromine with tetracyclo[3.2.0.02,7.04,6]heptane1,2

1980 ◽  
Vol 58 (13) ◽  
pp. 1327-1333 ◽  
Author(s):  
Dennis G. Garratt
Keyword(s):  
Ion Pairs ◽  
Molecular Bromine ◽  
Competitive Edge ◽  
Solvent Systems ◽  
Ionic Addition

The ionic addition of molecular bromine to tetracyclo[3.2.0.02,7•04,6]heptane (quadricyclene) has been investigated in a variety of solvent Systems. Depending upon the nature of the solvent, three or more of six dibromo and five solvent-incorporated adducts are isolable. A mechanism involving a series of ion-pairs and competitive edge-on vs. corner (end-on) attack is proposed.

MD Studies of Transport in Polymer-Salt Complexes: A Progress Report

1990 ◽  
Vol 210 ◽  
Author(s):  
M. Forsyth ◽  
V. A. Payne ◽  
M. A. Ratner ◽  
S. W. De Leeuw ◽  
D. F. Shriver
Keyword(s):  
Polymer Electrolytes ◽  
Ion Pairs ◽  
Solvent Molecule ◽  
Ion Pair ◽  
Pair Formation ◽  
Progress Report ◽  
Lennard Jones ◽  
Solvent Model ◽  
Solvent Systems ◽  
Dynamics Simulations

AbstractMolecular dynamics simulations performed on highly concentrated Coulomb/solvent systems are used to help interpret the transport mechanism in polymer ionics. Using simple Coulomb and Lennard-Jones forces among the ions and a solvent model of a fixed dipole contained in a spherical solvent particle, we investigated the nature of ion pair formation and stability. For a model NaI system, we find that ion pairs decrease with increase in solvent dipole moment or temperature. The latter observation is at variance with experimental results on polymer electrolytes, probably because of entropy terms that do not occur with our simple solvent molecule.

Chemistry of gaseous ion pairs produced by thermal collisions

1980 ◽  
Vol 77 ◽  
pp. 759-768 ◽  
Author(s):  
R. Stephen Berry
Keyword(s):  
Ion Pairs

On the Origins of Administrative Rent: Doing Business in a Russian Region N

2010 ◽  
pp. 58-80 ◽  
Author(s):  
A. Oleinik
Keyword(s):  
Rent Seeking ◽  
Individual Decision ◽  
Resource Rent ◽  
Competitive Edge ◽  
Doing Business ◽  
Russian Region ◽  
Positive Gain ◽  
Access To The Field ◽  
Quantitative And Qualitative Methods

In the article two types of rent are differentiated: resource rent and administrative rent. The latter is linked to restrictions on the access to the field of interactions. The contribution of the theory of public choice and the theory of rent-seeking and directly-unproductive activities is further developed by shifting the emphasis from individual decision-making to interactions between three actors: C, who controls access to the field, A, who gets a competitive edge as a result, and B, who assumes a subjacent position with regard to both A and C, yet still receives a positive gain from transacting. Domination by virtue of a constellation of As, Bs, and Cs interests is illustrated with the help of an in-depth case study of a Russian region. This study combines quantitative and qualitative methods, as well as their triangulation.

Levy oration - 2015

2016 ◽  
Vol 78 ◽  
pp. 7-10
Author(s):  
C.W. Holmes
Keyword(s):  
New Zealand ◽  
Dairy Farming ◽  
Competitive Edge

New Zealand dairy farming has lost its competitive edge

Hydrogen-Bonded Solvent Systems

1969 ◽  
Vol 67 (1_3) ◽  
pp. 168-168
Author(s):  
H. G. Hertz
Keyword(s):  
Solvent Systems ◽  
Hydrogen Bonded

VANILLINSÄURE ALS ENDPRODUKT DES STOFFWECHSELS VON ADRENALIN UND NORADRENALIN. II.

1963 ◽  
Vol 44 (1) ◽  
pp. 101-106 ◽  
Author(s):  
Wilhelm Dirscherl ◽  
Helmut Thomas
Keyword(s):  
Rat Liver ◽  
Paper Chromatography ◽  
Column Chromatography ◽  
Vanillic Acid ◽  
Hippuric Acid ◽  
Single Spot ◽  
Solvent Systems ◽  
Perfusion Experiment ◽  
Kinetics Of

ABSTRACT Perfusion of rat liver with vanillic acid yielded only one metabolite. In paper chromatography with three different solvent systems, the substance showed the same RF-values as vanillyolglycine (3-methoxy-4-hydroxyhippuric acid) and in mixed chromatograms there was only one single spot. After separation by column chromatography, the UV- and IRspectra of the reaction product were identical with those of 3-methoxy4-hydroxy-hippuric acid. During the perfusion experiment, the kinetics of the conjugation were investigated.

OPTIMIZATION OF THIN LAYER CHROMATOGRAPHY METHODS FOR SEPARATION AND IDENTIFICATION OF ANTIDEPRESSANTS IN THEIR MIXTURE

2014 ◽  
Vol 21 (1) ◽  
pp. 11-15
Author(s):  
Daiva Kazlauskienė ◽  
Guoda Kiliuvienė ◽  
Palma Nenortienė ◽  
Giedrė Kasparavičienė ◽  
Ieva Matukaitytė
Keyword(s):  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Solvent System ◽  
Ammonia Solution ◽  
Relative Standard ◽  
Rf Values ◽  
Solvent Systems ◽  
Paroxetine Hydrochloride ◽  
Fluvoxamine Maleate ◽  
Layer Chromatography

By conducting the toxicological analysis it is meaningful to determine the analytical system that could identify simultaneously several medicinal preparations quickly and precisely. The purpose of this work was to create and validate the method of thin-layer chromatography that would be suitable to separate the components of antidepressant mixture (amitriptyline hydrochloride, paroxetine hydrochloride, sertraline hydrochloride, fluvoxamine maleate and buspirone hydrochloride) and to identify them. The system was validated with regard to the sensitivity, repetition of data, resistance and particularity. The solvent systems with potential of high separation of components in their mixture were created: acetonitrile, methanol, ammonia solution 25 percent (85:10:5); acetonitrile, methanol, ammonia solution 25 percent (75:20:5); dichlormethane, 1,4-dioxane, ammonia solution 25 percent (50:45:5); dichlormethane, 1,4-dioxane, ammonia solution 25 percent (42:55:3); trichlormethane, 1,4-dioxane, ammonia solution 25 percent (25:70:5); trichlormethane, 1,4-dioxane, ammonia solution 25 percent (60:36:4). One of the most suitable solvent systems for separation of the analyzed mixture (sertraline, amitriptyline, paroxetine, buspirone, fluvoxamine) was determined – acetonitrile, methanol, ammonia solution 25 percent (85:10:5). When this solvent system was used, the average Rf values of the analyzed compounds differed the most. Validation was conducted – the relative standard deviation (RSD, percent) of the average Rf value of the analyzed compounds varied from 0,6 to 1,8 percent and did not exceed the permissible error of 5 percent. The sensitivity of methodology was determined by assessing the intensity of the mixture’s spots on the chromatographic plate. The detection limit of buspirone was 0,0012 µg; sertraline – 0,0008 µg; amitriptyline – 0,0004 µg; fluvoxamine – 0,0004 µg; paroxetine – 0,0008 µg. The resistance of results to the changed conditions – it was determined that when the amounts of the solvents acetonitrile and methanol were increased or decreased to two milliliters, the average Rf values of the analyzed compounds did not change statistically significantly

Ion Pairing and Dielectric Decrement in Glycosaminoglycan Brushes

2020 ◽  
Author(s):  
James Sterling ◽  
Wenjuan Jiang ◽  
Wesley M. Botello-Smith ◽  
Yun L. Luo
Keyword(s):  
Molecular Dynamics ◽  
Ion Pairs ◽  
Mean Field ◽  
Salt Bridge ◽  
Ion Pairing ◽  
Donnan Potential ◽  
Mean Field Models ◽  
Ion Exclusion ◽  
Dynamics Simulations ◽  
Contact Ion Pairs

Molecular dynamics simulations of hyaluronic acid and heparin brushes are presented that show important effects of ion-pairing, water dielectric decrease, and co-ion exclusion. Results show equilibria with electroneutrality attained through screening and pairing of brush anionic charges by cations. Most surprising is the reversal of the Donnan potential that would be expected based on electrostatic Boltzmann partitioning alone. Water dielectric decrement within the brush domain is also associated with Born hydration-driven cation exclusion from the brush. We observe that the primary partition energy attracting cations to attain brush electroneutrality is the ion-pairing or salt-bridge energy associated with cation-sulfate and cation-carboxylate solvent-separated and contact ion pairs. Potassium and sodium pairing to glycosaminoglycan carboxylates and sulfates consistently show similar abundance of contact-pairing and solvent-separated pairing. In these crowded macromolecular brushes, ion-pairing, Born-hydration, and electrostatic potential energies all contribute to attain electroneutrality and should therefore contribute in mean-field models to accurately represent brush electrostatics.

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