Source:http://linkedlifedata.com/resource/pubmed/id/10698581
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
1-2
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pubmed:dateCreated |
2000-3-29
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pubmed:abstractText |
We have studied the catalytic two-electron reduction of 3-chloro-2,4-pentanedione by cobalt(I) salen electrogenerated at a glassy carbon cathode in acetonitrile containing tetramethylammonium tetrafluoroborate. When cobalt(I) salen is electrogenerated at -0.65 V (a potential that is 30 mV more negative than the peak potential for the reversible one-electron reduction of cobalt(II) salen), the carbon-chlorine bond of 3-chloro-2,4-pentanedione is catalytically cleaved to form 2,4-pentanedion-3-ate; this anion can be protonated either by adventitious water or by a deliberately added proton donor to produce 2,4-pentanedione, or the anion can be trapped with iodoethane to give 3-ethyl-2,4-pentanedione. However, when cobalt(I) salen is electrogenerated at -0.40 V (a potential at which the rate of generation of cobalt(I) salen is relatively small), the 2,4-pentanedion-3-ate, resulting from the catalytic two-electron cleavage described above, can deprotonate unreduced starting material to form 3-chloro-2,4-pentanedion-3-ate and 2,4-pentanedione. In further work, we have found that 2,4-pentanedion-3-ate can be oxidized directly to form the corresponding radical which couples to yield 3,4-diacetyl-2,5-hexanedione. Chemically produced 2,4-pentanedion-3-ate reacts with electrogenerated cobalt(III) salen to give a dionylcobalt(III) salen species which undergoes a one-electron reduction to liberate cobalt(II) salen and the dionate. In addition, cobalt(II) salen reacts with molecular oxygen to give cobalt(III) salen and superoxide, and the latter reduces 3-chloro-2,4-pentanedione to form chloride ion, the 2,4-pentanedion-3-yl radical, and molecular oxygen.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Acetonitriles,
http://linkedlifedata.com/resource/pubmed/chemical/Borates,
http://linkedlifedata.com/resource/pubmed/chemical/Chelating Agents,
http://linkedlifedata.com/resource/pubmed/chemical/Cobalt,
http://linkedlifedata.com/resource/pubmed/chemical/Ethylenediamines,
http://linkedlifedata.com/resource/pubmed/chemical/Indicators and Reagents,
http://linkedlifedata.com/resource/pubmed/chemical/Oxygen,
http://linkedlifedata.com/resource/pubmed/chemical/Pentanones,
http://linkedlifedata.com/resource/pubmed/chemical/Quaternary Ammonium Compounds,
http://linkedlifedata.com/resource/pubmed/chemical/Superoxides,
http://linkedlifedata.com/resource/pubmed/chemical/disalicylaldehyde ethylenediamine
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pubmed:status |
MEDLINE
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pubmed:month |
Feb
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pubmed:issn |
0731-7085
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
19
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
193-203
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pubmed:dateRevised |
2006-11-15
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pubmed:meshHeading |
pubmed-meshheading:10698581-Acetonitriles,
pubmed-meshheading:10698581-Borates,
pubmed-meshheading:10698581-Catalysis,
pubmed-meshheading:10698581-Chelating Agents,
pubmed-meshheading:10698581-Cobalt,
pubmed-meshheading:10698581-Electrochemistry,
pubmed-meshheading:10698581-Electrodes,
pubmed-meshheading:10698581-Electrolysis,
pubmed-meshheading:10698581-Ethylenediamines,
pubmed-meshheading:10698581-Gas Chromatography-Mass Spectrometry,
pubmed-meshheading:10698581-Indicators and Reagents,
pubmed-meshheading:10698581-Oxidation-Reduction,
pubmed-meshheading:10698581-Oxygen,
pubmed-meshheading:10698581-Pentanones,
pubmed-meshheading:10698581-Quaternary Ammonium Compounds,
pubmed-meshheading:10698581-Spectrophotometry, Ultraviolet,
pubmed-meshheading:10698581-Superoxides
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pubmed:year |
1999
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pubmed:articleTitle |
Electrochemical behavior of 3-chloro-2,4-pentanedione in the presence of cobalt salen.
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pubmed:affiliation |
Department of Chemistry, Indiana University, Bloomington 47405, USA.
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pubmed:publicationType |
Journal Article
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