Kinetic insights into the reactivity of the intermediates generated from hydrogen peroxide and diiron(III) complex with tris(picolyl)amine (TPA)
| Autor: | Xianru Sun, Sergiy V. Kryatov, Elena V. Rybak-Akimova |
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| Rok vydání: | 2013 |
| Předmět: |
Tris
Phenol Phosphines Pyridines Hydrogen Peroxide Photochemistry Medicinal chemistry Ferric Compounds Inorganic Chemistry Reaction rate chemistry.chemical_compound Kinetics Reaction rate constant chemistry Coordination Complexes Electrophile Amine gas treating Reactivity (chemistry) Hydrogen peroxide Oxidation-Reduction Phosphine |
| Zdroj: | Dalton transactions (Cambridge, England : 2003). 42(13) |
| ISSN: | 1477-9234 |
| Popis: | Two intermediates (2 and 3) are formed consecutively in the reaction of a diiron(III) complex [Fe(III)(2)(μ-O)(OH)(H(2)O)(TPA)(2)](ClO(4))(3) (TPA = tris(2-pyridylmethyl)amine, tris(picolyl)amine) with H(2)O(2) in CH(3)CN at -40 °C. Low-temperature stopped-flow studies showed that both species are kinetically competent in oxidation of phosphines and phenols. The first intermediate (2) reacts with substrates very rapidly (second-order rate constants reach 10(5)-10(6) M(-1) s(-1) for substituted triarylphosphines and 10(3)-10(5) M(-1) s(-1) for substituted phenols), in keeping with a diiron(IV)-oxo formulation. The second intermediate (3), a mixed-valent Fe(III)Fe(IV) species, is more stable than 2, and reacts with substrates more slowly (second-order rate constants range from 150 to 550 M(-1) s(-1) for triaryl phosphine oxidation, and from 18 to 790 M(-1) s(-1) for phenol oxidation). Reaction rates increase with increasing electron donating abilities of substituents, indicating that both 2 and 3 act as electrophilic oxidants. |
| Databáze: | OpenAIRE |
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