Wyniki wyszukiwania - BazTech

1

Kinetics of Promazine and Methylene Blue Oxidation by Manganese(III) Diphosphate Complex

Topolski A., Wiśniewska J., Impert O., Kita P.

Polish Journal of Chemistry

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2009

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Vol. 83, nr 4

697-702

2

Kinetics of Chromium(V) Formation from Some Tetraazamacrocyclic Chromium(III) Complexes in Alkaline Media

Impert O., Katafias A., Kita P., Wrzeszcz G.

Polish Journal of Chemistry

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2008

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Vol. 82, nr 8

1673-1673

3

Kinetics of Chromate(III) Oxidation by Hydrogen Peroxide in Alkaline Solutions - Revisited

Impert O., Katafias A., Kita P., Woroniecka M.

Polish Journal of Chemistry

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2008

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Vol. 82, nr 5

1121-1126

4

Kinetics of a Bipyridine Chromium(III) Complex Oxidation by Hexacyanoferrate(III) in Strongly Alkaline Media

Impert O., Kujawski M., Kita P.

Polish Journal of Chemistry

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2006

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Vol. 80, nr 2

351-355

5

Kinetics and Mechanism of trans-[Cr(cyca)(OH)F]+Complex Oxidation by [Fe(CN)6]3- Ion in Strongly Alkaline Aqueous Solutions

Katafias A., Impert O., Kita P., Wrzeszcz G., Dominiak D.

Polish Journal of Chemistry

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2006

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Vol. 80, nr 6

931-941

EN

Oxidation of the trans-[Cr(cyca)(OH)F]+ complex, where cyca = meso-5,5,7,12,14- hexamethyl-1,4,8,11-tetraazacyclotetradecane, by [Fe(CN)6]3- ion in strongly alkaline media has been studied. A long-lived intermediate chromium(V) species was detected basing on the EPR signal at giso = 1.986. The hyperfine structure of the main EPR signal is consistent with the d1-electron interactions with four equivalent or nearly equivalent nitrogen nuclei and [CrV=O(cycaox)]3+ formula, where cycaox = oxidized cyca, can be postulated for the intermediate CrV complex. Kinetics of the rate limiting stage - electron transfer from the chromium(III) complex - has been studied in details applying an excess of the reductant and [OH-] at ionic strength equal 2.0 M. The rate law: -d[FeIII] dt = d[CrIV] dt = 0,5k cb K[OH-] 1+ 0,5(K-1)[OH-] [CrIII][FeIII] is consistent with an outer-sphere electron transfer from the conjugate base (cb) of the reductant formed in a preequilibrium (K) step. Reactivity of the deprotonated chromium(III) complex is characterized by kcb 298 = 9.7,deltaH#= (44.1š 0.5) kJ_mol-1, deltaS# = (-78.0 š 2.0) JxK-1xmol-1 and the preequilibrium step -by K298 = 0.237, delta H0 = (11.5 š 1.8) kJ_mol-1, delta S0 = (26.6 š 5.8) JxK-1xmol-1.

6

Kinetics of Nitrito-O Substitution in a Macrocyclic Chromium(III) Complex in Alkaline Media

Katafias A., Madej E., Impert O., Cywińska B., Kita P.

Polish Journal of Chemistry

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2004

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Vol. 78 / nr 3

457-462

7

Reactivity of Two Protolytic Forms of Methylene Blue in Reaction with Ascorbic Acid

Pietkiewicz-Graczyk A., Impert O., Katafias A., Kita P.

Polish Journal of Chemistry

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2003

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Vol. 77 / nr 4

475-480