Current Search: Enzyme kinetics (x)
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Title
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Kinetics and mechanistic studies of molybdenum(2) oxygen(3) (diethyl dtc)(2) (THF)(2) iodine(2).
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Creator
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Abburi, Chakravarthi., Florida Atlantic University, Baird, Donald M.
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Abstract/Description
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A study of the kinetic behavior of the oxygen atom transfer reaction of Mo2o3 (Et2dtc)2 (THF) 2I2, (I), with a variety of derivatives of pyridine N-oxides has been performed. The reaction behaves in pseudo-first-order fashion under conditions of excess N-oxide. Plots of kobs vs. [N-oxide] do not give straight lines, while plots of 1/kobs vs. 1/[N-oxide] are linear. The rate constant k is taken as the inverse of the slope of this latter plot. There is a marked dependence of the rate on the...
Show moreA study of the kinetic behavior of the oxygen atom transfer reaction of Mo2o3 (Et2dtc)2 (THF) 2I2, (I), with a variety of derivatives of pyridine N-oxides has been performed. The reaction behaves in pseudo-first-order fashion under conditions of excess N-oxide. Plots of kobs vs. [N-oxide] do not give straight lines, while plots of 1/kobs vs. 1/[N-oxide] are linear. The rate constant k is taken as the inverse of the slope of this latter plot. There is a marked dependence of the rate on the functional group in the 4-position of the pyridine ring with the relative rates -CH3 > -H > -Cl > -CN. The above observations can be used to support a mechanism in which a rapid pre-equilibrium, with a large equilibrium constant, is followed by a rate-determining breaking of the Mo-O-Mo bridge.
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Date Issued
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1992
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PURL
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http://purl.flvc.org/fcla/dt/14828
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Subject Headings
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Enzyme kinetics, Molybdenum enzymes, Chemical kinetics
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Format
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Document (PDF)
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Title
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Studies towards a catalytic asymmetric isomerization of manganese complexed alkynes to allenes using chiral bases.
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Creator
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He, Chang., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
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Abstract/Description
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The conversion of alkynyl carbonyls to allenyl carbonyls via manganese mediated coordination followed by a base-catalyzed isomerization was carried out using a range of chiral and achiral amine bases. Chiral amidine and chiral DBU derivatives were synthesized to carry out the isomerization enantioselectively. We employed HPLC equipped with a chiral column to determine the enantiomeric excess. We also proved that the mechanism of that the manganese-coordinated alkyne/allene rearrangement...
Show moreThe conversion of alkynyl carbonyls to allenyl carbonyls via manganese mediated coordination followed by a base-catalyzed isomerization was carried out using a range of chiral and achiral amine bases. Chiral amidine and chiral DBU derivatives were synthesized to carry out the isomerization enantioselectively. We employed HPLC equipped with a chiral column to determine the enantiomeric excess. We also proved that the mechanism of that the manganese-coordinated alkyne/allene rearrangement reaction involved an intermediate cumenolate. It was also confirmed that amine base with pKa lower than that of DBU (pKa = 13.6) would not carry out the isomerization. Alkoxy base were also used in isomerization and the mechanism was also investigated.
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Date Issued
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2009
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PURL
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http://purl.flvc.org/FAU/192983
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Subject Headings
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Enzyme kinetics, Organometallic compounds, Synthesis, Asymmetric synthesis, Methathesis (Chemistry), Carbonyl compounds, Synthesis
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Format
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Document (PDF)