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Direct Comparison of the Reactivity of Model Complexes for Compounds 0, I, and II in Oxygenation, Hydrogen‐Abstraction, and Hydride‐Transfer Processes
Author(s) -
Fertinger Christoph,
HessenauerIlicheva Natalya,
Franke Alicja,
van Eldik Rudi
Publication year - 2009
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200901804
Subject(s) - reactivity (psychology) , chemistry , hydride , catalysis , reaction rate constant , hydrogen atom abstraction , hydrogen , reactive intermediate , photochemistry , reaction rate , combinatorial chemistry , kinetics , organic chemistry , alternative medicine , medicine , physics , pathology , quantum mechanics
Abstract The iron(III) meso ‐tetramesitylporphyrin complex is a good biomimetic to study the catalytic reactions of cytochrome P450. All of the three most discussed reactive intermediates concerning P450 catalysis (namely, Cpd 0, Cpd I, and Cpd II) can be selectively produced, identified, and stabilized for many minutes in solution at low temperature by choosing appropriate reaction conditions. In this way, their reactivity against various substrates was determined by utilizing low‐temperature rapid‐scan UV/Vis spectroscopy. Since all reactive intermediates are derived from a single model complex, the results of these kinetic measurements provide for the first time a full comparability of the determined rate constants for the three intermediates. The rate constants reveal a significant dependence of the reactivity on the type of reaction (e.g., oxygenation, hydrogen abstraction, or hydride transfer), which closely correlates with the chemical nature of Cpds 0, I, and II. The detailed knowledge of the reactivity of these intermediates provides a valuable tool to evaluate their particular role in biological systems.