ChemInform Abstract: REACTIVITIES OF FREE IONS AND CROWN ETHER-COMPLEXED ION PAIRS IN THE PROTONATION OF FLUORENYLSODIUM BY 9-METHYLFLUORENE

1983 ◽  
Vol 14 (20) ◽  
Author(s):  
K.-H. WONG ◽  
J. SMID
Keyword(s):  
Crown Ether ◽  
Ion Pairs ◽  
Free Ions

Formation of ion pairs in rubidium-tetrahydrofuran crown ether solutions

1980 ◽  
Vol 84 (8) ◽  
pp. 842-847 ◽  
Author(s):  
U. Eliav ◽  
Haim Levanon
Keyword(s):  
Crown Ether ◽  
Ion Pairs

Synthesen und Kristallstrukturen der Kronenether-Komplexe (18-Krone-6) · 2CH3CN, [Na-15-Krone-5][ReO4] · CH3CN und [Na-15-Krone-5]PF6 / Syntheses and Crystal Structures of the Crown Ether Complexes (18-Crown-6) · 2 CH3CN, [Na-15-Crown-5][ReO4] · CH3CN, and [Na-15-Crown-5]PF6

1989 ◽  
Vol 44 (12) ◽  
pp. 1524-1530 ◽  
Author(s):  
Frank Weller ◽  
Harald Borgholte ◽  
Harald Stenger ◽  
Stefan Vogler ◽  
Kurt Dehnicke
Keyword(s):  
Crown Ether ◽  
Sodium Fluoride ◽  
Ion Pairs ◽  
Sodium Atom ◽  
Acetonitrile Solution ◽  
Space Group ◽  
Crown Ether Complexes ◽  
Water Space ◽  
Ether Molecule ◽  
Oxygen Atoms

Single crystals of (18-crown-6) · 2 CH3CN were obtained by cooling a solution of 18-crown-6 in acetonitrile to 4 °C. Space group P21/n, Z = 2, 629 observed independent reflexions, R = 0.062. Lattice dimensions at 19°C: a = 911.7(1), b = 852.0(1), c = 1370.0(2) pm; β = 104.61(1)°. The compound forms a molecular structure with approximate D3d symmetry of the crown ether molecule, and C—H ··· O interactions of the acetonitrile molecules with the crown ether, the Η···Ο distances being 243, 253, and 267 pm, respectively.[Na-15-crown-5][ReO4] · CH3CN is formed as a by-product of the reaction of ReNCl4 with sodium fluoride in acetonitrile in the presence of 15-crown-5 and traces of water. Space group Ρ 1̄ , Ζ = 2, 3107 observed independent reflexions, R = 0.045. Lattice dimensions at 19°C: a = 823.4(1), b = 1078.8(1), c = 1204.0(1) pm; α = 112.40(1)°, β = 94.35(1)°, γ = 104.63(1)°. The compound forms ion pairs, in which the sodium atom is sixfold coordinated by the five oxygen atoms of the crown ether molecule, as well as by one oxygen atom of the ReO4- ion, which is only slightly distorted. The bond length Na—OReO3 is 237.8(8) pm, the bond angle NaORe is 164.3(5)°.[Na-15-crown-5]PF6 is formed in the reaction of [ReCl3(NSCl)2 · POC13] with sodium fluoride in acetonitrile solution in the presence of 15-crown-5. Space group Pna21, Ζ = 4, 1130 observed independent reflexions, R = 0.123. The high R value is due to disorder of the skeletal atoms of the crown ether molecule. The compound forms ion pairs, in which the sodium atom is sevenfold coordinated by the five oxygen atoms of the crown ether molecule, as well as by two fluorine atoms of the PF6- ion with Na—F bond lengths of 240(2), and 246(2) pm, respectively.

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
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