[en] Radiolytic and photochemical transformations of aqueous solutions containing phenanthroline ions (phenH⁺) have been repeatedly studied. It is well known that two semireduced forms - protonated electron adduct (phenH⁺₂) and H-adduct (H · phenH⁺) - are formed in a reducing medium. In acid solutions, these two short-lived species possess individual optical absorption spectra with maxima at 520 nm (phenH⁺₂), and a 450 and 680 nm (H · phenH⁺), respectively. In this work, the authors studied the reactivity of these species to uranyl ions using a pulse radiolysis technique

[en] The kinetics and mechanism of the reduction of ferric 1,10 orthophenanthroline by uranium (IV) trans - 1,2 - cyclohexanediaminetetraacetate was investigated in aqueous hydrochloric acid at 300 deg. C, at ionic strength 0.01-mole dm/sup -3/ and pH 3.5. Rate law for the formation of [Fe (opt)/sub 3/ ]/sup 2+/ was established through spectroscopic measurements at constant and varying pH by isolation method. Order of reaction with respect to each reactant ([U(IV) DCTA] and [Fe (opt)/sub 3/]/sup 3+/ was investigated by plotting a graph of ln A/sub number infinity number/-A/sub t/ vs time at different temperature ranges. Each reactant was found to follow first order. Different thermodynamic functions for the reaction were E/sub a/ = 35 plus minus 0.6 kJ mol/sup -1/, delta H/sup number / 2.4 plus minus 0.2 kJ mol/sup -1/ and S/sup number/ = -149 +- 3 J mol/sup -1/k/sup -1/. Activation energy for the reaction was calculated with the help of Arrhenius equation. Other activation parameters (delta S/sup number/, delta H/sup number/) were determined from the slope and intercept of Eyring equation. At different pH values the rate law was observed as rate = K k/sup 1/ [H/sup +/]/sup n/ [U (IV) DCTA] Fe (opt)/sub 3//sup +3/, where K is equilibrium constant for the protonation reaction [U(IV)DCTA] + [H/sup +] [U(IV) DCTA H/sup +] and k/sub 1/ is the specific rate constant for the redox reaction [U(IV) DCTA H/sup +/ + [Fe(opt)/sub 3/]/sup +] + [Fe(opt)sup 3/]/sup 2+/. (author)

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[en] The mathematical modeling method has been employed to study evaporation kinetics of volatile coordination compounds accompanied by formation of non-volatile products as a result of oligomerization. The mathematical model is plotted as a system of differential equations based on the mass action law. Potentialities of modeling are considered, using by way of example, the study of sublimation processes of lanthanum acetylacetonate different ligand complex with o-phenanthroline. Solution of the reverse and direct problems permitted calculation of rate constants of all the processes and ascertaining of changes in the mole content of all the reagents in time

[en] Mathematical design of experiments was used to select optimal conditions for luminescence determination of ruthenium with 1,10-phenanthroline. If an icandescent lamp with a colour filter SS-4 was used as excitation source, the limit of detection for ruthenium was 5x10^-4 μg/ml. 800-Fold excess of rhodium (4), 400-fold of palladium (2), 1000-fold of osmium (4), 300-fold of iridium (4), 4000-fold of platinum (4) and, in the presence of EDTA, 2000-fold excess of lead (2) and 800-fold of bismuth (3) do not interfere with the determination of 0.1 μg of ruthenium. The method developed was used to determine ruthenium in sulphide coppper-nickel ores. Some luminescence characteristics of ruthenium (2)-complex were estimated

[en] Complex formation of all the series of rare earth with o-phenanthroline is studied. Using the method of pH-titration curves of formation of complexes are obtained, their stability constants being found. Reliability of the results, obtained using the method of pH-titration is reaffirmed spectrophotometrically. The data obtained are used to describe extraction equilibria in the lanthanoid-o-phenanthroline-caproic acid system

[en] By the methods pf pH-potentiometry, photocolorimetry and electron spectroscopy europium(III), samarium(III) and platinum(II) interaction with ascorbic acid and 1,10-phenanthroline is studied. Stability of acid and neutral ascorbate samarium complexes is determined. Heteroligand ascorbate-phenanthrolinate samarium(III) and platinum(II) complexes are separated from aqua-ethanol solution

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[en] Potentiometric method was used to study complex formation of cadmium nitrate with o-phenanthroline in aqueous-dioxane solutions, containing 25, 50 and 75 vol. % of organic solvent. The values of stability constants of complexes and o-phenanthroline pKsub(a) were determined. It was shown that stability of o- phenanthroline complexes decreases with increase of dioxane concentration. The index of o-phenanthroline acidic dissociation constant changes similarly