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.

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.

Colorimetric Determination of Fluoride in Drinking Groundwater using a Polymeric Zirconium Complex of 5-(2-Carboxyphenylazo)-8-Hydroxyquinoline

2013 ◽  
Vol 12 (7) ◽  
pp. 460-465
Author(s):  
Sameer Amereih ◽  
Zaher Barghouthi ◽  
Lamees Majjiad
Keyword(s):  
Drinking Water ◽  
Detection Limit ◽  
Complex Formation ◽  
Molar Absorptivity ◽  
Colorimetric Determination ◽  
Zirconium Complex ◽  
Reliable Determination ◽  
Percentage Recovery ◽  
Quantitation Limit

A sensitive colorimetric determination of fluoride in drinking water has been developed using a polymeric zirconium complex of 5-(2-Carboxyphenylazo)-8-Hydroxyquinoline as fluoride reagents. The method allowed a reliable determination of fluoride in range of (0.0-1.5) mg L-1. The molar absorptivity of the complex formation is 7695 ± 27 L mol-1 cm-1 at 460 nm. The sensitivity, detection limit, quantitation limit, and percentage recovery for 1.0 mg L-1 fluoride for the proposed method were found to be 0.353 ± 0.013 μg mL-1, 0.1 mg L-1, 0.3 mg L-1, and 101.7 ± 4.1, respectively.

Benzyl ethers of methyl α-D-glucopyranoside

1980 ◽  
Vol 45 (7) ◽  
pp. 1959-1963 ◽  
Author(s):  
Dušan Joniak ◽  
Božena Košíková ◽  
Ludmila Kosáková
Keyword(s):  
Kinetic Study ◽  
Spectrophotometric Determination ◽  
Reductive Cleavage ◽  
Ether Bond ◽  
Benzyl Ethers ◽  
Acid Catalyzed ◽  
Model Substances ◽  
Hydrolysis Of

Methyl 4-O-(3-methoxy-4-hydroxybenzyl) and methyl 4-O-(3,5-dimethoxy-4-hydroxybenzyl)-α-D-glucopyranoside and their 6-O-isomers were prepared as model substances for the ether lignin-saccharide bond by reductive cleavage of corresponding 4,6-O-benzylidene derivatives. Kinetic study of acid-catalyzed hydrolysis of the compounds prepared was carried out by spectrophotometric determination of the benzyl alcoholic groups set free, after their reaction with quinonemonochloroimide, and it showed the low stability of the p-hydroxybenzyl ether bond.

scholarly journals The Mechanism of the Reaction of (Arylthio)trimethylgermanes with Benzyl Bromides Giving Aryl Benzyl Sulfides. A Kinetic Study

1987 ◽  
Vol 60 (11) ◽  
pp. 4061-4065 ◽  
Author(s):  
Seizi Kozuka ◽  
Shoji Tamura ◽  
Satoshi Ishibashi ◽  
Sadamu Ohya ◽  
Waichiro Tagaki
Keyword(s):  
Kinetic Study ◽  
Mechanism Of The Reaction
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