666-52-4Relevant articles and documents
Mechanisms of Oxidation of 2-Propanol by Polypyridyl Complexes of Ruthenium(III) and Ruthenium (IV)
Thompson, Mark S.,Meyer, Thomas J.
, p. 4106 - 4115 (1982)
Kinetic and mechanistic studies have been carried out on the oxidation of 2-propanol to acetone in water by RuIV(trpy)(bpy)O2+ (trpy is 2,2',2''-terpyridine; bpy is 2,2'-bipyridine) and in acetonitrile by RuIV(bpy)2(py)O2+ (py is pyridine).The reactions proceed by oxidation of 2-propanol by Ru(IV) followed by a slower oxidation by the Ru(III) complexes Ru(trpy)(bpy)OH2+ or Ru(bpy)2(py)OH2+.For the reactions: in water, kIV(25 deg C) = 6.7 * 10-2 M-1 s-1, ΔH = 9 +/- kcal/mol, ΔS = -34 +/- 4 eu, kH/kD = 18 +/- 3; in , kIII(25 deg C) = 6 * 10-5 M-1 s-1, ΔH = 19 +/- 2 kcal/mol, ΔS = -12 +/- 6 eu, kH/kD = 2.7 +/- 1.4.An 18O-labeling experiment in 2-propanol and a spectral experiment in CH3CN show that oxo transfer from the oxidant to the substrate does not occur.It is concluded that the most likely mechanism of oxidation for Ru(IV) is a concerted, two-electron hydride transfer from the α-C-H bond to RuIV=O with the oxo group acting as a lead-in atom to the Ru(IV) acceptor site.The Ru(III) reaction in water appears to occur by an initial one-electron, outer-sphere electron transfer.In acetonitrile there appears to be a change in mechanism for this reaction, apparently to a H-atom transfer, once again involving the α-C-H group.For this path: k(25 deg C) = (8+/- 2) * 10 -4 M-1 s-1, ΔH = 10 +/- 2 kcal/mol, ΔS = -38 +/- 7 eu, kH/kD 8.
BASE CATALYZED ENOLIZATION AND HYDROGEN EXCHANGE OF TRIFLUOROACETONE. A COMPARISON TO ACETONE
Jansen, Michael P.,Tidwell, Thomas T.
, p. 791 - 802 (1982)
The kinetics of the pyridine catalyzed hydrogen exchange of 1,1,1-trifluoroacetone in 50percent D2O-dioxane have been measured using 1H-NMR.Rates of hydrogen exchange of acetone were also measured under comparable conditions and the rate of deuterium uptake by trifluoroacetone was found to exceed that of acetone by a factor of 1700 at 25 deg C.However trifluoroacetone is known to be extensively hydrated under these conditions.The hydrogen exchange of trifluoroacetone is interpreted as most probably proceeding through proton abstraction by pyridine from the free ketone to form the enolate followed by deuteration on carbon, with the rate of proton abstraction from trifluoroacetone exceeding that of acetone by a factor of 105 to 106.Other possibilities are also considered.
Paulsen,Cooke
, p. 1560 (1963)
Phosphonium Phenolate Zwitterion vs Phosphonium Ylide: Synthesis, Characterization and Reactivity Study of a Trimethylphosphonium Phenolate Zwitterion
Xiao, Jing,Li, Qiang,Shen, Ruwei,Shimada, Shigeru,Han, Li-Biao
supporting information, p. 5715 - 5720 (2019/11/22)
4-Methoxy-3-(trimethylphosphonio)phenolate was obtained from a regioselective addition of PMe3 to p-quinone monoacetal. This compound undergoes hydrogen isotope exchange with D2O or CD3CN, and is capable of catalyzing H/D exchange of CD3CN with substrates bearing weakly acidic hydrogens. It exhibits similar reactivity to phosphorus ylides for olefinations of aldehydes. A possible tautomerization between the phosphonium phenolate zwitterion and phosphonium ylide is proposed for the first time to rationalize the unique reactivity.
Organocatalytic Imidazolium Ionic Liquids H/D Exchange Catalysts
Zanatta, Marcileia,Dos Santos, Francisco P.,Biehl, Cristina,Marin, Graciane,Ebeling, Gunter,Netz, Paulo A.,Dupont, Jairton
supporting information, p. 2622 - 2629 (2017/03/14)
Simple 1,2,3-trialkylimidazolium cation associated with basic anions, such as hydrogen carbonate, prolinate, and imidazolate, is an active catalyst for the H/D exchange reaction of various substrates using CDCl3 as D source, without the addition of any extra bases or metal. High deuterium incorporation (up to 49%) in acidic C-H bonds of ketone and alkyne substrates (pKa from 18.7 to 28.8) was found at room temperature. The reaction proceeds through the fast and reversible deuteration of the 2-methyl H of the imidazolium cation followed by D transfer to the substrate. The IL acts as a neutral base catalyst in which the contact ion pair is maintained in the course of the reaction. The basic active site is due to the presence of a remote basic site in the anion namely, OH of bicarbonate, NH of prolinate, and activated water in the imidazolate anion. Detailed kinetic experiments demonstrate that the reaction is first order on the substrate and pseudozero order relative to the ionic liquid, due to the fast reversible reaction involving the deuteration of the ionic liquid by the solvent.
