1624-36-8Relevant academic research and scientific papers
Large primary kinetic isotope effects in the abstraction of hydrogen from organic compounds by a fluorinated radical in water
Cradlebaugh, Joseph A.,Zhang, Li,Shtarev,Smart, Bruce E.,Dolbier Jr., William R.
, p. 2087 - 2091 (2004)
Isotope effects have been measured for the abstraction of hydrogen from a series of organic substrates by the perfluoro radical, Na+ -O3SCF2CF2OCF2CF 2, in water. Both primary and secondary deuterium isotope effects were measured, with the primary isotope effects ranging in value from 4.5 for isopropanol to 19.6 for acetic acid. The values for the α- and β-secondary deuterium isotope effects were 1.06 and 1.035, respectively. It was concluded that tunneling contributes significantly to the production of the observed, large primary kinetic isotope effects in these C-H abstraction reactions.
Transition state for β-elimination of hydrogen from alkoxy groups on metal surfaces
Gellman, Andrew J.,Buelow, Mark T.,Street, Shane C.,Morton, Thomas Hellman
, p. 2476 - 2485 (2000)
Experimental investigations of β-hydrogen elimination from alkoxy and alkyl groups bound to a Cu(111) surface have been coupled with computational studies of gas-phase analogues to provide insight into the transition state for catalytic hydrogenation and dehydrogenation on metal surfaces. Previous studies have shown that fluorination increases the activation barrier (ΔEact) to β-hydrogen elimination in ethoxy groups (RCH2O(ad) → RCH=O(ad) + H(ad), where R = CH3, CFH2, CHF2, CF3) and propyl groups (RCH2CH2,(ad) → RCH=CH2,(ad)+ H(ad), where R = CH3, CF3) on the Cu(111) surface. The increase in barrier height with increasing fluorination was attributed to the inductive influence of fluorine, which energetically destabilizes a hydride-like transition state of the form [RCδ+...Hδ-]?. In this paper, deuterium kinetic isotope effects (DKIE) show that fluorination does not alter the mechanism for β-hydrogen elimination from ethoxy groups. Furthermore, the DKIE measurements confirm that the effects of fluorine on the kinetics of β-hydrogen elimination do not result from the change in mass when hydrogen is substituted by fluorine. A systematic study of fluorine substitution of surface-bound isopropoxy groups reveals combined steric and electronic effects. An excellent correlation is found between the ΔEact for β-hydrogen elimination in adsorbed alkoxy groups and the calculated reaction energetics (ΔHrxn) for gas-phase dehydrogenation of fluorinated alcohols in trans antiperiplanar conformations (e.g., RCH2OH(g) → RCH=O(g) + H2,(g), where the hydroxyl hydrogen is antiperiplanar to a carbon and the oxygen is antiperiplanar to a fluorine). Hammett plots for β-hydrogen elimination give a reaction parameter of ρ = -26. These correlations both suggest that the transition state for β-hydrogen elimination develops a greater partial positive charge on the carbinol carbon than is found in the adsorbed reactant. Furthermore, the transition state is energetically late in the reaction coordinate for β-hydrogen elimination.
Stereochemistry of the Coenzyme B12-mediated Rearrangement of 2-Aminoethan-1-ol by Ethanolamine Ammonia-lyase
Gani, David,Wallis, O. Caryl,Young, Douglas W.
, p. 898 - 899 (1982)
Reaction kinetics and 2H n.m.r. spectra of reaction products show independently that the coenzyme B12-mediated rearrangement of 2-aminoethan-1-ol by the enzyme ethanolamine ammonia-lyase proceeds with migration of the (1S)-hydrogen.
Bioconversion of D-glucose in heavy water: Effect of water isotopomeric composition on deuterium fragment distribution in ethanol
Sakhabutdinov,Bisikalo,Kushnarev,Rokhin,Kulagina
experimental part, p. 2058 - 2061 (2011/05/07)
The relative distribution of deuterium between methyl and methylene groups in ethanol at the bioconversion of D-glucose in heavy water was studied.
Stereospecificity of hydride transfer during the dismutation of aldehydes catalyzed by alcohol dehydrogenases
Velonia,Smonou
, p. 3119 - 3123 (2007/10/03)
The stereochemistry of the oxidation of aldehydes to acids with alcohol dehydrogenases was studied with respect to the selectivity towards the cofactor.
Kinetics and Deuterium Kinetic Isotope Effects for the Thermal Sigmatropic Rearrangements of cis,cis-1,3,5-Octatriene
Baldwin, John E.,Reddy, V. Prakash
, p. 8051 - 8056 (2007/10/02)
Thermal isomerizations of cis,cis-1,3,5-octatriene at 60-111 deg C occur with activation parameters log A = 9.1 and Ea = 21.3 (to cis,cis,cis-2,4,6-octatriene) and Ea = 20.2 kcal mol-1 (to cis,cis,trans-2,4,6-octatriene).P
THE rs STRUCTURES OF PROPYL FLUORIDE AND DIFFERENCES IN STRUCTURES BETWEEN ROTATIONAL ISOMERS
Hayashi, Michiro,Fujitake, Masaharu
, p. 9 - 24 (2007/10/02)
Microwave spectra of trans and gauche propyl fluoride and its isotopically substituted species have been measured.The rs structures of the trans and gauche isomers of this molecule are determined from the observed moments of inertia.It is found that the CCC angle values are largely different between two isomers, while the CCF angle values stay unchanged.The rs structures of ethyl fluorosilane and ethylmethyl sulfide are re-examined in order to compare the results with those of propyl fluoride.The differences in the structural parameter values between the rotational isomers are discussed for the present molecules and the analogous molecules such as ethanethiol and ethaneselenol.
Elimination of Molecular Hydrogen and Methane from Collision-Activated Alkoxide Negative Ions in the Gas Phase. An ab initio and Isotope Effect Study
Hayes, Roger N.,Sheldon, John C.,Bowie, John H.,Lewis, David E.
, p. 1197 - 1208 (2007/10/02)
Ab initio calculations indicate that the collisional induced losses of molecular hydrogen from the ethoxide negative ion and methane from the t-butoxide negative ion to be stepwise processes in which the key intermediates are -...MeCHO> and -...Me2CO> respectively.Deuterium kinetic isotope effects observed for these and other alkoxide negative ions are in accord with the operation of a stepwise reaction.
