Oxygen activation with transition metal complexes in aqueous solution
Abstract
Coordination to transition-metal complexes changes both the thermodynamics and kinetics of oxygen reduction. Some of the intermediates (superoxo, hydroperoxo, and oxo species) are close analogues of organic oxygen-centered radicals and peroxides (ROO{sm_bullet}, ROOH, and RO{sm_bullet}). Metal-based intermediates are typically less reactive, but more persistent, than organic radicals, which makes the two types of intermediates similarly effective in their reactions with various substrates. The self-exchange rate constant for hydrogen-atom transfer for the couples Cr{sub aq}OO{sup 2+}/Cr{sub aq}OOH{sup 2+} and L{sup 1}(H{sub 2}O)RhOO{sup 2+}/L{sup 1}(H{sub 2}O)RhOOH{sup 2+} was estimated to be 10{sup 1 {+-} 1} M{sup -1} s{sup -1}. The use of this value in the simplified Marcus equation for the Cr{sub aq}O{sup 2+}/Cr{sub aq}OOH{sup 2+} cross reaction provided an upper limit k{sub CrO,CrOH} {le} 10{sup (-2{+-}1)} M{sup -1} s{sup -1} for Cr{sub aq}O{sup 2+}/Cr{sub aq}OH{sup 2+} self-exchange. Even though superoxo complexes react very slowly in bimolecular self-reactions, extremely fast cross reactions with organic counterparts, i.e., acylperoxyl radicals, have been observed. Many of the intermediates generated by the interaction of O{sub 2} with reduced metal complexes can also be accessed by alternative routes, both thermal and photochemical.
- Authors:
- Publication Date:
- Research Org.:
- Ames Lab., Ames, IA (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC)
- OSTI Identifier:
- 976960
- Report Number(s):
- IS-J 7514
Journal ID: 0020-1669; TRN: US201009%%137
- DOE Contract Number:
- DE-AC02-07CH11358
- Resource Type:
- Journal Article
- Journal Name:
- Inorganic Chemistry
- Additional Journal Information:
- Journal Volume: 49; Journal Issue: 8
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; AQUEOUS SOLUTIONS; KINETICS; OXYGEN; PEROXIDES; RADICALS; SUBSTRATES; THERMODYNAMICS; TRANSITION ELEMENTS
Citation Formats
Bakac, Andreja. Oxygen activation with transition metal complexes in aqueous solution. United States: N. p., 2010.
Web. doi:10.1021/ic9015405.
Bakac, Andreja. Oxygen activation with transition metal complexes in aqueous solution. United States. https://doi.org/10.1021/ic9015405
Bakac, Andreja. 2010.
"Oxygen activation with transition metal complexes in aqueous solution". United States. https://doi.org/10.1021/ic9015405.
@article{osti_976960,
title = {Oxygen activation with transition metal complexes in aqueous solution},
author = {Bakac, Andreja},
abstractNote = {Coordination to transition-metal complexes changes both the thermodynamics and kinetics of oxygen reduction. Some of the intermediates (superoxo, hydroperoxo, and oxo species) are close analogues of organic oxygen-centered radicals and peroxides (ROO{sm_bullet}, ROOH, and RO{sm_bullet}). Metal-based intermediates are typically less reactive, but more persistent, than organic radicals, which makes the two types of intermediates similarly effective in their reactions with various substrates. The self-exchange rate constant for hydrogen-atom transfer for the couples Cr{sub aq}OO{sup 2+}/Cr{sub aq}OOH{sup 2+} and L{sup 1}(H{sub 2}O)RhOO{sup 2+}/L{sup 1}(H{sub 2}O)RhOOH{sup 2+} was estimated to be 10{sup 1 {+-} 1} M{sup -1} s{sup -1}. The use of this value in the simplified Marcus equation for the Cr{sub aq}O{sup 2+}/Cr{sub aq}OOH{sup 2+} cross reaction provided an upper limit k{sub CrO,CrOH} {le} 10{sup (-2{+-}1)} M{sup -1} s{sup -1} for Cr{sub aq}O{sup 2+}/Cr{sub aq}OH{sup 2+} self-exchange. Even though superoxo complexes react very slowly in bimolecular self-reactions, extremely fast cross reactions with organic counterparts, i.e., acylperoxyl radicals, have been observed. Many of the intermediates generated by the interaction of O{sub 2} with reduced metal complexes can also be accessed by alternative routes, both thermal and photochemical.},
doi = {10.1021/ic9015405},
url = {https://www.osti.gov/biblio/976960},
journal = {Inorganic Chemistry},
number = 8,
volume = 49,
place = {United States},
year = {Mon Apr 12 00:00:00 EDT 2010},
month = {Mon Apr 12 00:00:00 EDT 2010}
}