An ESR Study of Mn(II) Complexes in Water-Methanol Mixed Solvents

1971 ◽  
Vol 26 (11) ◽  
pp. 1091-1096 ◽  
Author(s):  
James R. Bard ◽  
James O. Wear
Keyword(s):  
Aqueous Solution ◽  
Dielectric Constant ◽  
Complex Formation ◽  
Mole Fraction ◽  
Coordination Sphere ◽  
Mixed Solvents ◽  
Solvent Composition ◽  
Significant Feature ◽  
Similar Data ◽  
Methanol Content

0.01 ᴍ solutions of Mn (ClO4)2, MnCl2 and MnSO4 in water-methanol mixtures were studied at 25 °C to determine the effect of these anions and of solvent composition on the ESR intensity and linewidth of Mn(II). A significant feature of the data was the large difference between the intensity of Mn(ClO4)2 and that for MnCl2 and MnSO4 in solutions containing greater than about 0.5 mole fraction methanol. A plot of linewidth versus mole fraction methanol shows little difference between Mn(ClO4)2 and MnCl2 but an increasingly greater difference between these salts and MnSO4 with increasing methanol content. These results are interpreted as being due to first coordination sphere complex formation in solutions containing Cl⊖, while the SO42⊖ data are affected by both first and second coordination sphere complexes depending upon the solvent dielectric constant. The Mn(ClO4)2 data were interpreted as showing that the primary solvation sphere of the Mn(II) ions was changing as the composition of the bulk solvent changed. These results are compared with similar data in aqueous solution and confirm that complex formation involving Cl⊖ or SO42⊖ ions and Mn(II) is extensive in water-methanol mixtures.

scholarly journals Dielectric and Excess Dielectric Constants of Acetonitrile + Butyl Amine, + Ethylamine, and + Methylamine at 303, 313, and 323 K

2013 ◽  
Vol 2013 ◽  
pp. 1-4 ◽  
Author(s):  
Ch. V. V. Ramana ◽  
A. B. V. Kiran Kumar ◽  
M. Ashok Kumar ◽  
M. K. Moodley
Keyword(s):  
Dielectric Constant ◽  
Intermolecular Interactions ◽  
Mole Fraction ◽  
Entire Range ◽  
Binary Systems ◽  
Mixed Solvents ◽  
Dielectric Constants ◽  
Complete Mole ◽  
Butyl Amine ◽  
Mole Fraction Range

The dielectric constants and excess dielectric constants of the binary systems: acetonitrile + butyl amine, + ethylamine and + methylamine have been studied at 303, 313, and 323 K temperatures and over the complete mole fraction range. The dielectric constants for these mixtures were measured using a microcontroller based system. The results are positive over the entire range of composition. Symmetrical curves were observed for the systems in which the maximum occurs approximately at 0.7-mole fraction of acetonitrile. The results are discussed in terms of intermolecular interactions. The investigation of dielectric constant of mixed solvents bearing amines aims at better comprehension of their biological, chemical, pharmaceutical, technological, and laboratory applications.

A kinetic study of nickel(II)–murexide complex formation in dimethylsulfoxide/nitromethane mixed solvents

1976 ◽  
Vol 54 (5) ◽  
pp. 706-710 ◽  
Author(s):  
James P. K. Tong ◽  
Cooper H. Langford
Keyword(s):  
Complex Formation ◽  
Kinetic Study ◽  
Mixed Solvents ◽  
Solvent Composition ◽  
Nmr Data ◽  
Inert Solvent ◽  
Coordinate Sphere ◽  
Mechanism Of The Reaction

The rates of nickel(II)–murexide complex formation were studied in dimethylsulfoxide/nitromethane mixed solvents at 25 °C with the latter being an "inert" solvent, to elucidate the mechanism of the reaction. Results do not fit in detail with a D mechanism and the five-coordinated intermediate interpretation. Id mechanisms are able to explain the observations with and without invoking a nitromethane-containing intermediate, Ni(DMSO)5NM2+. Both mechanisms were tested with the aid of nmr data on solvation (second coordinate sphere nitromethane population). Ligand solvation unavoidably plays a major role in the determination of the encounter as well as the complex formation equilibrium. The simplest mechanism assumes an Id process in which the probability of encounter between Ni(DMSO)62+ and murexide ion is quite sensitive to solvent composition.

Effect of dielectric constant on the rate of electron spin exchange of Fremy's salt in solution

1986 ◽  
Vol 51 (11) ◽  
pp. 2433-2436 ◽  
Author(s):  
Hamza A. Hussain ◽  
Waleed A. A. Kuder
Keyword(s):  
Aqueous Solution ◽  
Dielectric Constant ◽  
Electron Spin ◽  
Spin Exchange ◽  
Bimolecular Collisions

The rate of electron spin exchange in aqueous solution of potassium nitrosodisulphonate K2(SO3)2NO, has been investigated by ESR and found to depend on the dielectric constant of the medium. This observation lead to the calculation of the collision diameter 2 nm which corresponds to bimolecular collisions between species carrying two nagative charges.

Über den Mechanismus der Bildung von Polyanionen in wäßriger Lösung. Zum Bildungsmechanismus eines Polytetramolybdations [Mo4O144-]n / On the Mechanism of Formation of Polyanions in Aqueous Solution. Concerning the Mechanism of Formation of a Polytetramolybdate Ion [Mo4O144-]n

1976 ◽  
Vol 31 (6) ◽  
pp. 737-748 ◽  
Author(s):  
Karl-Heinz Tytko
Keyword(s):  
Aqueous Solution ◽  
Coordination Sphere ◽  
Analytical Formula ◽  
Reaction Pathways ◽  
Mechanism Of Formation ◽  
X Ray ◽  
Theoretical Considerations

Possible structures and the pertinent reaction pathways for the polymetalate ion present in a slightly soluble polymetalate having the analytical formula A2O · 2 MOs have been derived on the basis of theoretical considerations. Structure and kind of combination of the tetrameric units of one of the possibilities are in agreement with the results of X-ray structure analyses. First the previously proposed planar tetrametalate ion [M4O12(OH)4]4--is formed by stepwise aggregation according to an addition mechanism. This species undergoes a rearrangement of the coordination sphere of two of the M atoms and is then subject to a polycondensation resulting in a polytetrametalate chain, [M4O144-]n.

Schiff base equilibria. II. Beryllium complexes of N-n-butylsalicylideneimine and the hydrolysis of the Be2+ ion

1965 ◽  
Vol 18 (5) ◽  
pp. 651 ◽  
Author(s):  
RW Green ◽  
PW Alexander
Keyword(s):  
Aqueous Solution ◽  
Schiff Base ◽  
Complex Formation ◽  
Distribution Coefficient ◽  
Dilute Aqueous Solution ◽  
The Stability ◽  
Ph Range ◽  
Hydrolysis Of ◽  
Beryllium Complexes ◽  
Equilibria In Aqueous Solution

The Schiff base, N-n-butylsalicylideneimine, extracts more than 99.8% beryllium into toluene from dilute aqueous solution. The distribution of beryllium has been studied in the pH range 5-13 and is discussed in terms of the several complex equilibria in aqueous solution. The stability constants of the complexes formed between beryllium and the Schiff base are log β1 11.1 and log β2 20.4, and the distribution coefficient of the bis complex is 550. Over most of the pH range, hydrolysis of the Be2+ ion competes with complex formation and provides a means of measuring the hydrolysis constants. They are for the reactions: Be(H2O)42+ ↔ 2H+ + Be(H2O)2(OH)2, log*β2 - 13.65; Be(H2O)42+ ↔ 3H+ + Be(H2O)(OH)3-, log*β3 -24.11.

Complex Formation in the Ternary System Tl(III)−CN-−Cl-in Aqueous Solution. A205Tl NMR Study

1996 ◽  
Vol 35 (24) ◽  
pp. 7074-7081 ◽  
Author(s):  
Katja E. Berg ◽  
Johan Blixt ◽  
Julius Glaser
Keyword(s):  
Aqueous Solution ◽  
Complex Formation ◽  
Ternary System ◽  
Nmr Study
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