Absorption spectra of aqueous solutions of europium dichloride

1966 ◽  
Vol 5 (6) ◽  
pp. 575-576 ◽  
Author(s):  
V. I. Ganopol'skii ◽  
V. F. Barkovskii ◽  
N. P. Ipatova
Keyword(s):  
Aqueous Solutions ◽  
Absorption Spectra

scholarly journals Spectral Probe for Electron Transfer and Addition Reactions of Azide Radicals with Substituted Quinoxalin-2-Ones in Aqueous Solutions

2021 ◽  
Vol 22 (2) ◽  
pp. 633
Author(s):  
Konrad Skotnicki ◽  
Slawomir Ostrowski ◽  
Jan Cz. Dobrowolski ◽  
Julio R. De la Fuente ◽  
Alvaro Cañete ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Aqueous Solutions ◽  
Absorption Spectra ◽  
Density Functional ◽  
Reduction Potential ◽  
Biological Significance ◽  
Radical Cations ◽  
Basis Sets ◽  
Double Bonds ◽  
Reduction Potentials

The azide radical (N3●) is one of the most important one-electron oxidants used extensively in radiation chemistry studies involving molecules of biological significance. Generally, it was assumed that N3● reacts in aqueous solutions only by electron transfer. However, there were several reports indicating the possibility of N3● addition in aqueous solutions to organic compounds containing double bonds. The main purpose of this study was to find an experimental approach that allows a clear assignment of the nature of obtained products either to its one-electron oxidation or its addition products. Radiolysis of water provides a convenient source of one-electron oxidizing radicals characterized by a very broad range of reduction potentials. Two inorganic radicals (SO4●−, CO3●−) and Tl2+ ions with the reduction potentials higher, and one radical (SCN)2●− with the reduction potential slightly lower than the reduction potential of N3● were selected as dominant electron-acceptors. Transient absorption spectra formed in their reactions with a series of quinoxalin-2-one derivatives were confronted with absorption spectra formed from reactions of N3● with the same series of compounds. Cases, in which the absorption spectra formed in reactions involving N3● differ from the absorption spectra formed in the reactions involving other one-electron oxidants, strongly indicate that N3● is involved in the other reaction channel such as addition to double bonds. Moreover, it was shown that high-rate constants of reactions of N3● with quinoxalin-2-ones do not ultimately prove that they are electron transfer reactions. The optimized structures of the radical cations (7-R-3-MeQ)●+, radicals (7-R-3-MeQ)● and N3● adducts at the C2 carbon atom in pyrazine moiety and their absorption spectra are reasonably well reproduced by density functional theory quantum mechanics calculations employing the ωB97XD functional combined with the Dunning’s aug-cc-pVTZ correlation-consistent polarized basis sets augmented with diffuse functions.

scholarly journals Electronic Absorption Spectra of Aqueous Solutions and Adsorbed Layers of 1-Methyl-4-(4-diethylaminophenylazo)pyridinium iodide.

1991 ◽  
pp. 1582-1587 ◽  
Author(s):  
Michio KOBAYASHI ◽  
Yoshio MAEDA ◽  
Hitoshi TOKUNAGA ◽  
Norio TAKAHASHI ◽  
Toshihiko HOSHI ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Absorption Spectra ◽  
Electronic Absorption ◽  
Electronic Absorption Spectra ◽  
Adsorbed Layers

Absorption spectra of the OH and O- radicals in aqueous solutions

1993 ◽  
Vol 41 (3) ◽  
pp. 503-505 ◽  
Author(s):  
Gidon Czapski ◽  
Benon H.J. Bielski
Keyword(s):  
Aqueous Solutions ◽  
Absorption Spectra

scholarly journals Spectrophotometric investigations of the reaction between gold(III) and potassium iodide

2000 ◽  
Vol 65 (5-6) ◽  
pp. 345-352 ◽  
Author(s):  
Vesna Vasic ◽  
Suzana Premovic ◽  
Mira Cakar ◽  
Bojan Radak ◽  
Gordana Milovanovic
Keyword(s):  
Complex Formation ◽  
Aqueous Solutions ◽  
Absorption Spectra ◽  
Potassium Iodide ◽  
Equilibrium Constants ◽  
Hydrogen Ion

The equilibria of the complex formation between AuCl4-n(OH)n - and I- was studied spectrophotometrically in aqueous solutions containing KI:Au(III)?2 in the acidity range from 1 M HCl to pH 7 at 25?C. From the hydrogen ion and Cl-ion dependence of the absorption spectra, it was found that AuCl2I2 - and Au(OH)2I2 - complexes were formed. The equilibrium constants of complex formation were determined.

Cefoxitin interferes with the "Clini-Skreen" column method for urinary 17-hydroxycorticosteroids.

1987 ◽  
Vol 33 (7) ◽  
pp. 1219-1222
Author(s):  
M H Kroll ◽  
A J Jackson ◽  
R J Elin
Keyword(s):  
Aqueous Solutions ◽  
Absorption Spectra ◽  
Rate Constants ◽  
Equilibrium Constants ◽  
Molar Absorptivity ◽  
The Other ◽  
Absorbance Maximum ◽  
Column Method ◽  
Apparent Concentration

Abstract Cefoxitin interferes with determination of urinary 17-hydroxycorticosteroids. The apparent concentration of hormone is increased from three- to 10-fold in samples from patients receiving cefoxitin when the Amberlite XAD-2 "Clini-Skreen" column is used. To determine the mechanism of interference, we reacted aqueous solutions of cefoxitin, cortisol, cortisone, and 11-deoxycortisol with phenylhydrazine; recorded the adsorption spectra; and determined the molar absorptivities and the equilibrium and rate constants. Also, we recorded the absorption spectra of phenylhydrazine with eight other cepha antibiotics and benzylpenicillin. Cortisol, cortisone, 11-deoxycortisol, and cefoxitin react with phenylhydrazine and absorb light with superimposable spectra and absorption maxima of 410 nm. The other antibiotics react with phenylhydrazine but absorbance maxima of the products vary, none being at 410 nm. Cortisol, cortisone, and 11-deoxycortisol react with phenylhydrazine 35-fold faster, have equilibrium constants ninefold greater, and have molar absorptivities 1.6 times that of cefoxitin. Thus, cefoxitin interferes with determination of urinary 17-hydroxycorticosteroids by forming a chromophore with the same absorbance maximum and with a molar absorptivity similar to cortisol, but much more slowly.

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