Vinylic cations from solvolysis. XX. Ion pairs and free ions in the solvolysis and isomerization of 1,2-dianisyl-2-phenylvinyl halides and mesylates. Use of cis-trans isomerization as a mechanistic tool

1975 ◽  
Vol 97 (4) ◽  
pp. 821-835 ◽  
Author(s):  
Zvi Rappoport ◽  
Yitzhak Apeloig
Keyword(s):  
Ion Pairs ◽  
Free Ions ◽  
Trans Isomerization

A comparison of acetone and poly(propylene glycol) as solvents for lithium triflate and lithium perchlorate

1991 ◽  
Vol 69 (12) ◽  
pp. 1980-1984 ◽  
Author(s):  
James R. Stevens ◽  
Per Jacobsson
Keyword(s):  
Propylene Glycol ◽  
Ion Pairs ◽  
Lithium Perchlorate ◽  
Lithium Triflate ◽  
Free Ions ◽  
Lower Dielectric Constant ◽  
Current Controversy ◽  
Raman Modes ◽  
Poly Propylene ◽  
Key Words Acetone

Solutions of LiCF3SO3 and LiClO4 in acetone and in poly(propylene glycol) (PPG 400 and PPG 4000) have been compared by studying the nondegenerate, symmetric stretch (A1,SO3) and (A1,ClO4) Raman modes. The Raman spectra contain bands due to the symmetric stretching motion of the "free" anion and due to the symmetric stretching motion of anions in ion aggregates. It is concluded that "free" ions, ion pairs, triplets, and aggregates are present. Although PPG has a much lower dielectric constant, it is a better solvent for these salts than the dipolar aprotic acetone. These findings have ramifications on the current controversy of whether "free" ions are present at all in polyether–salt complexes such as PPG 4000/LiCF3SO3. Key words: acetone, poly(propylene glycol), lithium triflate, lithium perchlorate, Raman.

The ionization and dissociation of triphenylmethyl chloride in 1,2-dichloroethane-styrene mixtures

1978 ◽  
Vol 31 (11) ◽  
pp. 2445 ◽  
Author(s):  
SS Bos ◽  
FE Treloar
Keyword(s):  
Mercuric Chloride ◽  
Cationic Polymerization ◽  
Equilibrium Constants ◽  
Ion Pairs ◽  
Free Ions

Triphenylmethyl chloride with mercuric chloride ionizes and dissociates in 1,2-dichloroethane and 1,2-dichloroethane-styrene mixtures into ion pairs and free ions. The values of the equilibrium constants for ionization to ion pairs and the subsequent dissociation of these show that the free ions are preferentially solvated by the added styrene. The consequences of this for the cationic polymerization of styrene are briefly discussed.

The absolute rate constants of anionic propagation by free ions and ion-pairs of living polystyrene

Polymer ◽  
1964 ◽  
Vol 5 ◽  
pp. 54-56 ◽  
Author(s):  
D.N. Bhattacharyya ◽  
C.L. Lee ◽  
J. Smid ◽  
M. Szwarc
Keyword(s):  
Rate Constants ◽  
Ion Pairs ◽  
Absolute Rate ◽  
Free Ions ◽  
The Absolute

scholarly journals Putting Together the Puzzle of Ion Transfer in Single-Digit Carbon Nanotubes: Ab Initio Meets Mean-Field

2021 ◽  
Author(s):  
Vadim Neklyudov ◽  
Viatcheslav Freger
Keyword(s):  
Ion Transport ◽  
Ab Initio ◽  
Ion Pairs ◽  
Mean Field ◽  
Transport Numbers ◽  
Thermodynamic Quantities ◽  
Mean Field Model ◽  
Single Digit ◽  
Free Ions ◽  
Anion Permeation

Abstract Nature employs channel proteins to selectively pass water across cell membranes, which inspires search for bio-mimetic analogues. Carbon nanotube porins (CNTPs) are intriguing mimics of water channels, yet ion transport in CNTPs still poses questions. As alternative to continuum models, here we present a molecular mean-field model, computing ab initio all required thermodynamic quantities for KCl salt and H+ and OH- ions present in water. Starting from water transfer, the model considers transfer of free ions, along with ion-pair formation to address ion-ion interactions. High affinity to hydroxide, suggested by experiments and making it dominant charge carrier in CNTP, is revealed as an exceptionally favorable transfer of KOH pairs. Nevertheless, free ions, coexisting with less mobile ion-pairs, apparently control ion transport. The model explains well the observed effects of salt concentration and pH on conductivity, transport numbers, anion permeation and its activation energies, and current rectification. The proposed approach is extendable to other sub-nanochannels and help design novel osmotic materials and devices.

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