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001-es BibID:	BIBFORM016482
Első szerző:	Popescu, Delia-Laura
Cím:	Thermodynamic, Electrochemical, High-Pressure Kinetic, and Mechanistic Studies of the Formation of Oxo Fe-IV-TAML Species in Water / Delia-Laura Popescu, Melanie Vrabel, Ariane Brausam, Peter Madsen, Gabor Lente, Istvan Fabian, Alexander D. Ryabov, Rudi van Eldik, Terrence J. Collins
Dátum:	2010
ISSN:	0020-1669
Megjegyzések:	Stopped-flow kinetic studies of the oxidation of Fe-II-TAML catalysts, [Fe{1,2-X2C6H2-4,5-(NCOCMe2NCO)(2)CMe2}-(OH2)](-) (1), by t-BuOOH and H2O2 in water affording Fe-IV species has helped to clarify the mechanism of the interaction of 1 with primary oxidants. The data collected for substituted Fe-III-TAMLs at pH 6.0-13.8 and 17-45 degrees C has confirmed that the reaction is first order both in 1 and in peroxides. Bell-shaped pH profiles of the effective second-order rate constants k(1) have maximum values in the pH range of 10.5-12.5 depending on the nature of 1 and the selected peroxide. The "acidic" part is governed by the deprotonation of the diaqua form of 1 and therefore electron-withdrawing groups move the lower pH limit of the reactivity toward neutral pH, although the rate constants k(1) do not change much. The dissection of k(1) into individual intrinsic rate constants k(1) ([FeL(OH2)(2)](-) + ROOH), k(2) ([FeL(OH2)OH)](2-) + ROOH), k(3) ([FeL(OH2)(2)](-) + ROO-), and k(4) ([FeL(OH2)OH)](2-) + ROO-) provides a model for understanding the bell-shaped pH-profiles. Analysis of the pressure and substituent effects on the reaction kinetics suggest that the k(2) pathway is (i) more probable than the kinetically indistinguishable k(3) pathway, and (ii) presumably mechanistically similar to the induced cleavage of the peroxide O-O bond postulated for cytochrome P450 enzymes. The redox titration of 1 by Ir-IV and electrochemical data suggest that under basic conditions the reduction potential for the half-reaction [(FeL)-L-IV(=O)(OH2)](2-) + e(-) + H2O -> [(FeL)-L-III(OH)(OH2)](2-) + OH- is close to 0.87 V (vs NHE).
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk coupled electron-transfer peroxide-activating catalysts tert-butyl hydroperoxide hydrogen-peroxide aqueous-solution oxoiron(iv) porphyrin oxidation catalysts compound-ii azo dyes iron(iii)
Megjelenés:	Inorganic Chemistry. - 49 : 24 (2010), p. 11439-11448. -
További szerzők:	Vrabel, Melanie Brausam, Ariane Madsen, Peter Lente Gábor (1973-) (vegyész) Fábián István (1956-) (vegyész) Ryabov, Alexander D. Eldik, Rudi, Van Collins, Terrence J.
Internet cím:	DOI Intézményi repozitóriumban (DEA) tárolt változat
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