[en] The conditions of pertechnetate ion precipitation with ferroin nitrate in nitric acid solutions were determined. The effect of precipitation condition on the composition and structure of ferroin pertechnetate complexes was analyzed. At aging of the precipitate in the mother liquor the formation of nitrosyl group in the complex was found, which is confirmed by appearance in the IR spectrum of the band at 1700 cm"-"1 belonging to the coordinated nitrosyl group. Analysis of the IR spectra of ferroin perrhenate and pertechnetate complexes showed that coordinated nitrosyl group is formed only in the presence of technetium in the complex structure. (author)

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[en] A method for determining sulfonate concentration in crude oils has been developed. It is based on the method of Taylor and Waters [Analyst(London), 97, 533 (1972)] in which a stable, chloroform-soluble complex is formed between sulfonates and ⁵⁹Fe labeled ferroin [Fe/super II/(1,10-phen)₃]²⁺. Application of this technique to crude oils has revealed that each oil has the ability to deactivate a specific amount of sulfonate

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[en] This study presents an experimental investigation of nonlinear dynamics in a modified Belousov-Zhabotinsky (BZ) reaction, in which the addition of 1,4-benzoquinone induced various complex behaviors such as mixed-mode oscillations and consecutive period-adding bifurcations. In addition, the presence of 1,4-benzoquinone significantly enhanced the photosensitivity of the ferroin-catalyzed BZ system, in which light-induced transitions between simple and complex oscillations have been achieved. Mechanistic study suggests that the influence of benzoquinone may arise from its interactions with the metal catalyst ferroin/ferriin, where cyclic voltammograms illustrate that the presence of benzoquinone causes an increase in the redox potential of ferroin/ferriin couple, which may consequently alternate the oxidation and reduction paths of the catalyst

[en] A catalytic kinetic methods of analysis is not really of much value in practice compared to many other methods, but such methods find important applications for the estimation of trace or ultra-trace quantities of different elements which cannot be done by spectrophotometrically or by any other convenient method (except, such ultra-sensitive method as neutron activation). In the title reaction, Ru^III can potentially catalyse in the concentration range of ppm or less, and from the measurement of rate of the process, Ru^III can be estimated. (author). 4 refs., 1 fig

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[en] A method is suggested for the indirect determination of cerium(III) ions in the presence of a high excess of tetravalent cerium. Ce(III) is oxidized to Ce(IV) by tris(1,10-phenanthroline)iron(III) complex (ferriin) in the presence of sodium diphosphate, and the purple-red iron(II) complex (ferroin) formed is determined photometrically at 530 nm. Trivalent cerium can be determined in quantities of 0-400 μg/50 ml with a relative error of +-3.5%. Cerium(III) was determined in commercial cerium(IV) sulfate and cerium dioxide preparations. (author)

[en] The influence of NaClO₄, NaCl and Na₂SO₄ on the oxidation of Fe(phen)²⁺₃ by Ce(IV) was investigated by means of the stopped-flow method. At the concentrations range of NaClO₄ and NaCl 0.1 - 1.0 M the rate constant values decrease from 1.03.10⁵ to 0.56.10⁵ M^-1s^-1 and from 1.08.10⁵ to 0.81.10⁵ M^-1s^-1 respectively. In varying concentration of Na₂SO₄ solutions (0.05 - 0.35 M) the rate constant values decrease from 1.05.10⁵ M^-1s^-1 to 0.45.10⁵ M^-1s^-1. Taking into account the negative salt effect the mechanism of the reaction progress is proposed. (author)