ferryl-iron and methylphenylsulfide

The Fe

Topics: Kinetics; Ligands; Models, Molecular; Oxidants; Oxidation-Reduction

Which is better? The first detailed comparison of the reactivity of nonheme iron(IV)-imido versus nonheme iron(IV)-oxo intermediates with substrates is presented. The iron(IV)-imido variant reacts with sulfides five times faster than iron(IV)-oxo, whereas the reverse trend is observed for hydrogen atom abstraction. These observed trends are analyzed and explained.

Topics: Catalysis; Coordination Complexes; Crystallography, X-Ray; Imides; Iron; Kinetics; Molecular Conformation; Oxidants; Oxidation-Reduction; Sulfides; Thermodynamics; Tosyl Compounds

Cyclic voltammetry performed at rapid scan rates on cytochrome P450 from Pseudomonas putida (P450CAM) in didodecyldimethylammonium bromide (DDAB) films on graphite electrodes revealed a couple (E) at 830mV (vs Ag/AgCl). E was not significantly observed at scan rates less than 30V/s at room temperature, suggesting that the oxidized species is unstable. The lifetime of E could be prolonged at 4 degrees C, which allowed reversible access to E at scan rates as low as 1V/s. E was found to be sensitive to imidazole in solution and to variations in pH, suggesting that the redox reaction is occurring at the metal center (i.e., Fe(IV/III)). Electrolysis reactions with different P450 substrates revealed that the electrochemically generated high-valent species is able to convert thioanisole to methyl phenyl sulfoxide.

Topics: Cytochrome P-450 Enzyme System; Electrochemistry; Ferric Compounds; Iron; Oxidation-Reduction; Pseudomonas putida; Quaternary Ammonium Compounds; Sulfides; Sulfoxides