Studies on ion-association: Thiocyanate ion-pairs of Al(III), Ga(III) and In(III)

1968 ◽  
Vol 30 (9) ◽  
pp. 2417-2423 ◽  
Author(s):  
R.C. Das ◽  
A.C. Dash ◽  
J.P. Mishra
Keyword(s):  
Ion Pairs ◽  
Ion Association ◽  
Thiocyanate Ion

Octahedral cobalt(III) complexes in dipolar aprotic solvents. II. Association between cis- and trans-dichlorobisethylenediamine cobalt(III) cations,[Co en2 Cl2]+, and chloride and bromide ions in the solvents NN-dimethylformamide, dimethyl sulphoxide, and LVN-dimethylacetamide

1966 ◽  
Vol 19 (1) ◽  
pp. 43 ◽  
Author(s):  
WA Millen ◽  
DW Watts
Keyword(s):  
Spectrophotometric Method ◽  
Ion Pairs ◽  
Ion Association ◽  
Ion Pair ◽  
Association Constants ◽  
Dimethyl Sulphoxide ◽  
Aprotic Solvents ◽  
Ion Association Constants ◽  
Cis And Trans ◽  
Dipolar Aprotic Solvents

Ion association constants at 30� have been determined for the cis-[Co en, Cl2]+Cl- ion pair in NN-dimethylformamide (DMF), NN-dimethylacetamide (DMA), and at 20.0�, 25.0�, and 30.0� in dimethyl sulphoxide (DMSO), by a spectrophotometric method. Association constants for the cis-[Co en2 Cl2]+Br- and the trans- [Co en2 Cl2]+Cl- ion pairs have also been determined in DMF at 30�.

scholarly journals When spectroscopy fails: The measurement of ion pairing

2006 ◽  
Vol 78 (8) ◽  
pp. 1571-1586 ◽  
Author(s):  
Glenn Hefter
Keyword(s):  
Metal Ion ◽  
Chemical Speciation ◽  
Ion Pairs ◽  
Ion Association ◽  
Ion Pair ◽  
Association Constants ◽  
Spectroscopic Techniques ◽  
Association Equilibria ◽  
Solvent Molecules ◽  
Contact Ion Pairs

Spectroscopic techniques such as UV/vis, NMR, and Raman are powerful tools for the investigation of chemical speciation in solution. However, it is not widely recognized that such techniques do not always provide reliable information about ion association equilibria. Specifically, spectroscopic measurements do not in general produce thermodynamically meaningful association constants for non-contact ion pairs, where the ions are separated by one or more solvent molecules. Such systems can only be properly quantified by techniques such as dielectric or ultrasonic relaxation, which can detect all ion-pair types (or equilibria), or by traditional thermodynamic methods, which detect the overall level of association. Various types of quantitative data are presented for metal ion/sulfate systems in aqueous solution that demonstrate the inadequacy of the major spectroscopic techniques for the investigation of systems that involve solvent-separated ion pairs. The implications for ion association equilibria in general are briefly discussed.

Photochemistry of rhodamine dye salts involving intra-ion-pair electron transfer

2003 ◽  
Vol 81 (6) ◽  
pp. 789-798 ◽  
Author(s):  
Guilford Jones II ◽  
Xiaochun Wang ◽  
Jingqiu Hu
Keyword(s):  
Electron Transfer ◽  
Ethyl Acetate ◽  
Rhodamine 6G ◽  
Radical Pair ◽  
Ion Pairs ◽  
Ion Pair ◽  
Thiocyanate Ion ◽  
Rhodamine Dye ◽  
Triplet Radical Pair ◽  
Pair State

The electron-transfer photochemistry of rhodamine 6G thiocyanate ion pairs has been investigated. For dye in a low polarity solvent, such as ethyl acetate, the emission of rhodamine 6G is significantly quenched by thiocyanate counterions. Laser photolysis of rhodamine 6G and thiocyanate in ethyl acetate was studied in detail with the identification of the reduced rhodamine 6G radical species (λmax = 410 nm). The growth and decay of the R6G radical could be accounted for in part by a mechanism involving initial formation of dye triplet followed by electron transfer which provides a triplet radical-pair state on a µs timescale.Key words: electron transfer, ion pair, rhodamine 6G, triplet state.

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 Association Effects on Nuclear Magnetic Resonance Parameters of Aromatic Ions. II. The Anions of Carbazole and 4,5-Methylenephenanthrene

1971 ◽  
Vol 49 (9) ◽  
pp. 1377-1383 ◽  
Author(s):  
Richard H. Cox
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Alkali Metal ◽  
Chemical Shifts ◽  
Ion Pairs ◽  
Ion Association ◽  
Coupling Constants ◽  
Alkali Metal Cations ◽  
Aromatic Ions ◽  
Magnetic Resonance Parameters

The 1H n.m.r. spectra of carbazole nitranion, 4,5-methylene- and 9,10-dihydro-4,5-methylene-phenanthrene carbanions with various alkali metal cations have been analyzed in terms of chemical shifts and coupling constants. Chemical shifts of the anions depend upon cation and solvent and are related to the type of ion pairs present. The 7Li n.m.r. data indicate that Li is associated with the nitrogen of carbazole nitranion whereas with the 4,5-methylenephenanthrene carbanions, Li appears to be located in the π-cloud of the anions and associated equally with all carbons in the anion. The results are discussed in terms of the types of ion pairs present and the association of cation with anion.

scholarly journals An Equation for Computing Thermal Capacity of an Electrolyte in a Dissociated Solution

2019 ◽  
pp. 77-87
Author(s):  
T.E. Akhapkina ◽  
A.A. Gurov ◽  
S.N. Solovev ◽  
S.V. Kozhevnikova
Keyword(s):  
Ion Pairs ◽  
Ion Association ◽  
Electrolyte Solutions ◽  
Thermal Capacity ◽  
Solution Properties ◽  
Association Model

The authors used E.M. Kuznetsova's theory to derive an equation for computing thermal capacity of an electrolyte in a dissociated solution. This equation may also be used to determine such important characteristics as the constant and enthalpy of ion association in electrolyte solutions. This equation is derived from the simplest model, that of ion association, which allows certain solution properties to be adequately described as functions of concentration. The ion association model is based on the equilibrium between ions and ion pairs of the same kind that exists in electrolyte solutions

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