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Kinetics of Oxygen Transfer Reactions Involving Molybdenum Dithiolene Complexes

Lorber, Christian; Plutino, Rosaria; Elding, Lars Ivar LU and Nordlander, Ebbe LU (1997) In Journal of the Chemical Society, Dalton Transactions p.3997-4004
Abstract
Oxo transfer reactions from [MoO2(mnt)2]2– [mnt2– = 2,3-disulfanylmaleonitrile dianion (1,2-dicyanoethylenedithiolate)] to the abiological oxygen acceptors PPh3–xEtx (x = 0–3) have been studied spectrophotometrically in acetonitrile. The pseudo-first-order rate constants depend linearly on the concentration of the oxo acceptors. The sequence of reactivity is PEt3 > PEt2Ph > PEtPh2 > PPh3, reflecting the basicities of the phosphines, while the steric influence of the substituents on the phosphorus atom appears to be of minor importance. The activation entropies for the reaction with PEt3 and PPh3 are negative. These observations are in agreement with the proposal that in the intermediate the entering phosphine binds to the... (More)
Oxo transfer reactions from [MoO2(mnt)2]2– [mnt2– = 2,3-disulfanylmaleonitrile dianion (1,2-dicyanoethylenedithiolate)] to the abiological oxygen acceptors PPh3–xEtx (x = 0–3) have been studied spectrophotometrically in acetonitrile. The pseudo-first-order rate constants depend linearly on the concentration of the oxo acceptors. The sequence of reactivity is PEt3 > PEt2Ph > PEtPh2 > PPh3, reflecting the basicities of the phosphines, while the steric influence of the substituents on the phosphorus atom appears to be of minor importance. The activation entropies for the reaction with PEt3 and PPh3 are negative. These observations are in agreement with the proposal that in the intermediate the entering phosphine binds to the molybdenum complex through the oxygen ligand. Oxidation of HSO3– by [MoO2(mnt)2]2– has also been studied in acetonitrile and in acetonitrile–water mixtures. The reaction exhibits Michaelis–Menten behaviour. In CH3CN–H2O, the rate of the reaction increases as the water concentration decreases; the reacting species appears to be a product from the reaction of the molybdenum starting complex with water. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Molybdenum complexes, Oxygen atom transfer, Michaelis–Menten reaction, Activation entropy
in
Journal of the Chemical Society, Dalton Transactions
issue
21
pages
3997 - 4004
publisher
Royal Society of Chemistry
ISSN
0300-9246
DOI
10.1039/a704332e
language
English
LU publication?
yes
id
9410c910-0a36-4e1b-902a-1258c9508d43 (old id 960966)
date added to LUP
2008-08-14 14:53:52
date last changed
2017-05-29 11:37:36
@article{9410c910-0a36-4e1b-902a-1258c9508d43,
  abstract     = {Oxo transfer reactions from [MoO2(mnt)2]2– [mnt2– = 2,3-disulfanylmaleonitrile dianion (1,2-dicyanoethylenedithiolate)] to the abiological oxygen acceptors PPh3–xEtx (x = 0–3) have been studied spectrophotometrically in acetonitrile. The pseudo-first-order rate constants depend linearly on the concentration of the oxo acceptors. The sequence of reactivity is PEt3 > PEt2Ph > PEtPh2 > PPh3, reflecting the basicities of the phosphines, while the steric influence of the substituents on the phosphorus atom appears to be of minor importance. The activation entropies for the reaction with PEt3 and PPh3 are negative. These observations are in agreement with the proposal that in the intermediate the entering phosphine binds to the molybdenum complex through the oxygen ligand. Oxidation of HSO3– by [MoO2(mnt)2]2– has also been studied in acetonitrile and in acetonitrile–water mixtures. The reaction exhibits Michaelis–Menten behaviour. In CH3CN–H2O, the rate of the reaction increases as the water concentration decreases; the reacting species appears to be a product from the reaction of the molybdenum starting complex with water.},
  author       = {Lorber, Christian and Plutino, Rosaria and Elding, Lars Ivar and Nordlander, Ebbe},
  issn         = {0300-9246},
  keyword      = {Molybdenum complexes,Oxygen atom transfer, Michaelis–Menten reaction,Activation entropy},
  language     = {eng},
  number       = {21},
  pages        = {3997--4004},
  publisher    = {Royal Society of Chemistry},
  series       = {Journal of the Chemical Society, Dalton Transactions},
  title        = {Kinetics of Oxygen Transfer Reactions Involving Molybdenum Dithiolene Complexes},
  url          = {http://dx.doi.org/10.1039/a704332e},
  year         = {1997},
}