Formation of Contact Ion Pairs and Solvation of Li+Ion in Sulfones: Phase Diagrams, Conductivity, Raman Spectra, and Dynamics†

2010 ◽  
Vol 55 (5) ◽  
pp. 1958-1964 ◽  
Author(s):  
Dmytro O. Tretyakov ◽  
Vitaly D. Prisiazhnyi ◽  
Malik M. Gafurov ◽  
Kamil Sh. Rabadanov ◽  
Sviatoslav A. Kirillov
Keyword(s):  
Phase Diagrams ◽  
Raman Spectra ◽  
Ion Pairs ◽  
Li Ion ◽  
Contact Ion Pairs

Ion-ion-solvent interactions in solution. I. Solutions of LiClO4 in acetone

1982 ◽  
Vol 35 (9) ◽  
pp. 1775 ◽  
Author(s):  
DW James ◽  
RE Mayes
Keyword(s):  
Raman Band ◽  
Ion Pairs ◽  
Ion Association ◽  
Solvent Interactions ◽  
Solvation Numbers ◽  
Solvated Ions ◽  
Component Band ◽  
Li Ion ◽  
Contact Ion Pairs ◽  
Association Equilibrium

Vibrational spectra and 7Li, 13C and 35Cl n.m.r. spectra have been obtained for solutions of LiClO4 in acetone for salt concentrations from 0.05 to 6 M. Infrared spectra give qualitative indications of ion association. Analysis of the Raman band due to C-C stretching in acetone yields solvation numbers for the Li+ ion of the order of 3. Component band analysis of the ClO4- symmetric stretching vibrational band and the various n.m.r. spectra lead to the identification of solvent-separated ion pairs, contact ion pairs and ion aggregates, in addition to free solvated ions. The dependence on salt concentration of all four species has been determined. The association quotient for the association equilibrium (Li+)s(ClO4)- ↔ [Li+(acetone)ClO4-)s was determined to be 1.4 � 0.3 dm3 mol-1.

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.

Reversible fluorescent and colorimetric rhodamine based-chemosensor of Cu 2+ contact ion-pairs using a ditopic receptors

2015 ◽  
Vol 123 ◽  
pp. 204-211 ◽  
Author(s):  
Chatthai Kaewtong ◽  
Buncha Pulpoka ◽  
Thawatchai Tuntulani
Keyword(s):  
Ion Pairs ◽  
Ditopic Receptors ◽  
Contact Ion Pairs

scholarly journals Interactions of Na+ Cations with a Highly Charged Fatty Acid Langmuir Monolayer: Molecular Description of the Phase Transition

2019 ◽  
Author(s):  
Adrien Sthoer ◽  
Eric Tyrode
Keyword(s):  
Phase Transition ◽  
Surface Charge ◽  
Surface Potential ◽  
Arachidic Acid ◽  
Ion Pairs ◽  
Theoretical Models ◽  
Langmuir Monolayer ◽  
Vibrational Sum Frequency Spectroscopy ◽  
Ion Size ◽  
Contact Ion Pairs

Vibrational sum frequency spectroscopy has been used to study the molecular properties upon compression of a highly charged arachidic acid Langmuir monolayer, which displays a first order phase transition plateau in the surface pressure - molecular area (p-A) isotherm. By targeting vibrational modes from the carboxylic acid headgroup, alkyl chain, and interfacial water molecules, information regarding the surface charge, surface potential, type of ion pair formed, and conformational order of the monolayer could be extracted. The monolayer in the liquid expanded phase is found to be fully charged until reaching the 2D-phase transition plateau, where partial reprotonation, as well as the formation of COO⎺ Na<sup>+ </sup>contact-ion pairs, start to take place. In the condensed phase after the transition, three headgroup species, mainly hydrated COO⎺, COOH, and COO⎺ Na<sup>+ </sup>contact-ion pairs could be identified and their proportions quantified. Comparison with theoretical models shows that despite the low ionic strengths used (i.e. 10 mM), the predictions from the Gouy Chapman model are only adequate for the lowest surface densities, when the surface charge does not exceed -0.1 C/m<sup>2</sup>. In contrast, a modified Poisson-Boltzmann (MPB) model that accounts for the steric effects associated with the finite ion-size, captures many of the experimental observables, including the partial reprotonation, and surface potential changes upon compression. The agreement highlights the importance of hydronium ion – carboxylate interactions, as well as the layer of sodium ions packed at the steric limit, for explaining the phase transition behavior. The MPB model, however, does not explicitly consider the formation of contact ion pairs with the sodium counterion. The experimental results provide a quantitative molecular insight that could be used to test potential extensions to the theory.

Elektronentransfer und Ionenpaare, 15 [ 1– 3] Radikalanion und Radikal-Kontakt-Ionenpaare von Dimesityl-tetraketon / Electron Transfer and Ion Pairing, 15 [1-3] Radical Anion and Radical Ion Pairs of Dimesityl Tetraketone

1990 ◽  
Vol 45 (8) ◽  
pp. 1197-1204 ◽  
Author(s):  
H. Bock ◽  
P. Hänel ◽  
H.-F. Herrmann
Keyword(s):  
Electron Transfer ◽  
Radical Anion ◽  
Ion Pairs ◽  
Ion Pairing ◽  
Single Electron ◽  
Single Electron Transfer ◽  
Temperature Dependent ◽  
Contact Ion Pairs

The radical anion of dimesityltetraketone (ERed, I = -0.40 V) is easily generated in THF by potassium mirror/[2.2.2]-cryptand reduction. Its contact ion pairs with Na⊕, Cs⊕ and Ba⊕⊕ counter cations, prepared in THF solution by single electron transfer from the respective metals, are characterized by their ESR/ENDOR spectra, which exhibit temperature-dependent metal couplings of aNa⊕ = 0.061 mT (190 K), aCs⊕ = 0.021 mT (190 K), and aBa⊕⊕ = 0.145 mT (295 K).

scholarly journals Ionic transport in highly concentrated lithium bis(fluorosulfonyl)amide electrolytes with keto ester solvents: structural implications for ion hopping conduction in liquid electrolytes

2019 ◽  
Vol 21 (9) ◽  
pp. 5097-5105 ◽  
Author(s):  
Shinji Kondou ◽  
Morgan L. Thomas ◽  
Toshihiko Mandai ◽  
Kazuhide Ueno ◽  
Kaoru Dokko ◽  
...  
Keyword(s):  
Ion Transport ◽  
Ion Pairs ◽  
Ionic Transport ◽  
Hopping Conduction ◽  
Keto Ester ◽  
Liquid Electrolytes ◽  
Li Ion

The hopping/exchange-dominated Li ion transport is attributed to liquid electrolytes with solvent-bridged, chain-like Li ion coordination and aggregated ion pairs.

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