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Title: Identification and Characterization of Aqueous Ferryl(IV) Ion

Abstract

No abstract prepared.

Authors:
;
Publication Date:
Research Org.:
Ames Laboratory (AMES), Ames, IA
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
909876
Report Number(s):
IS-J 7195
TRN: US0703990
DOE Contract Number:
DE-AC02-07CH11358
Resource Type:
Journal Article
Resource Relation:
Journal Name: Ferrates (part of book)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; IRON IONS; DMSO; SULFOXIDES

Citation Formats

Oleg Pestovsky, and Andreja Bakac. Identification and Characterization of Aqueous Ferryl(IV) Ion. United States: N. p., 2007. Web.
Oleg Pestovsky, & Andreja Bakac. Identification and Characterization of Aqueous Ferryl(IV) Ion. United States.
Oleg Pestovsky, and Andreja Bakac. Tue . "Identification and Characterization of Aqueous Ferryl(IV) Ion". United States. doi:.
@article{osti_909876,
title = {Identification and Characterization of Aqueous Ferryl(IV) Ion},
author = {Oleg Pestovsky and Andreja Bakac},
abstractNote = {No abstract prepared.},
doi = {},
journal = {Ferrates (part of book)},
number = ,
volume = ,
place = {United States},
year = {Tue May 01 00:00:00 EDT 2007},
month = {Tue May 01 00:00:00 EDT 2007}
}
  • The reaction between ferrous ions and ozone in acidified aqueous solution generates a short-lived species (t{sub 1/2} as 7 sec), which was identified as high-spin pentaaquairon(IV) oxo dication (ferryl) by UV-Vis, Mossbauer, XAS spectroscopies, DFT calculations, {sup 18}O isotopic labeling, and conductometric kinetic studies. Kinetic and {sup 18}O isotopic labeling studies were used to determine the rate constant for the oxo group exchange between ferryl and solvent water, k{sub ex} = 1400 s{sup -1}. Oxidation of alcohols, aldehydes, and ethers by ferryl occurs by simultaneous hydrogen atom and hydride transfer mechanisms. Ferryl was also found to be an efficient oxygenmore » atom transfer reagent in the reactions with sulfoxides, a water soluble phosphine, and a thiolato-complex of cobalt(III). A quantitative and fast reaction between ferryl and DMSO (k{sub DMSO} = 1.3 x 10{sup 5} M{sup -1} s{sup -1}) produces methyl sulfone. This and some other findings unambiguously rule out ferryl as a Fenton intermediate.« less
  • PFe{sup II} and PFe{sup III}OH (P is a porphyrin dianion) catalyze the decomposition of tert-butyl hydroperoxide in toluene solution without appreciable attack on the porphyrin ligand. {sup 1}H NMR spectroscopic studies at low temperature ({minus}70{degree}C) give evidence for the formation of a high-spin, five-coordinate intermediate, PFe{sup III}OOC(CH{sub 3}){sub 3}. Organic products formed from this reaction are tert-butyl alcohol, di-tert-butyl peroxide, benzaldehyde, acetone, and benzyl-tert-butyl peroxide, which arise largely from a radical chain process initiated by the iron porphyrin but continuing without its intervention.
  • Time-resolved resonance Raman spectra have been recorded during the reaction of fully reduced (a{sup 2+}a{sub 3}{sup 2+}) cytochrome oxidase with dioxygen at room temperature. In the spectrum recorded at 800 {mu}s subsequent to carbon monoxide photolysis, a mode is observed at 790 cm{sup {minus}1} that shifts to 755 cm{sup {minus}1} when the experiment is repeated with {sup 18}O{sub 2}. The frequency of this vibration and the magnitude of the {sup 18}O{sub 2} isotopic frequency shift lead the authors to assign the 790-cm{sup {minus}1} mode to the Fe{sup IV}{double bond}O stretching vibration of a ferryl-oxo cytochrome a{sub 3} intermediate that occursmore » in the reaction of fully reduced cytochrome oxidase with dioxygen. The appearance and vibrational frequency of this mode were not affected when D{sub 2}O was used as a solvent. This result suggests that the ferryl-oxo intermediate is not hydrogen bonded. They have also recorded Raman spectra in the high-frequency region during the oxidase/O{sub 2} reaction that show that the oxidation of cytochrome a{sup 2+} is biphasic. These results on the kinetics of the redox activity of cytochrome a are consistent with the branched pathway discussed by Hill et al. for the oxidation of reduced cytochrome oxidase by O{sub 2} at room temperature.« less