A theoretical study of deuterium isotope effects in the reactions molecular hydrogen + methyl and atomic hydrogen + methane

1984 ◽  
Vol 88 (2) ◽  
pp. 221-232 ◽  
Author(s):  
George C. Schatz ◽  
Albert F. Wagner ◽  
Thomas H. Dunning
Keyword(s):  
Atomic Hydrogen ◽  
Molecular Hydrogen ◽  
Theoretical Study ◽  
Isotope Effects ◽  
Deuterium Isotope Effects

A theoretical study of conformational deuterium isotope effects and bond dissociation energies of diastereotopic hydrogens

1991 ◽  
Vol 69 (9) ◽  
pp. 1408-1412 ◽  
Author(s):  
Saul Wolfe ◽  
Chan-Kyung Kim
Keyword(s):  
Theoretical Study ◽  
Isotope Effects ◽  
Model Systems ◽  
Bond Dissociation Energies ◽  
Model Compounds ◽  
Bond Dissociation ◽  
Dissociation Energies ◽  
Deuterium Isotope Effects ◽  
Derivatives Of ◽  
Good Agreement

In the conformations that correspond to the C6-X1-C2-X3-C4 moieties of 1,3-dioxane, 1,3-dithiane, and cyclohexane in their chair conformations, the model systems CH2(OH)2, CH2(SH)2, and gauche-butane contain "axial" and "equatorial" hydrogens. The vibrational frequencies of the diastereomeric monodeuterated CHD derivatives of these model compounds have been computed ab initio at the 6-31G*//6-31G* level of theory, scaled by 0.9, and used to calculate the conformational deuterium isotope effects in these systems, as well as the stretching and bending components of these isotope effects. The results are in very good agreement with the experimental observations and with some of the interpretations given by Anet for the six-membered rings. Using an equation suggested by McKean, the scaled isolated stretching frequencies have been used to predict the bond dissociation energies of the diastereotopic hydrogens of these molecules. The results suggest that the preference for radical abstraction of the axial C2 hydrogen in a 1,3-dioxane will be diminished in cyclohexane, and reversed in a 1,3-dithiane. Key words: stereochemistry, isotope effects, bond dissociation energies.

Theoretical Study on the CuH (copper hydride) + H (atomic hydrogen) -> Cu (copper) + H2 (molecular hydrogen) reaction pathway

1986 ◽  
Vol 90 (2) ◽  
pp. 279-282 ◽  
Author(s):  
M. E. Ruiz ◽  
J. Garcia-Prieto ◽  
E. Poulain ◽  
G. A. Ozin ◽  
R. A. Poirier ◽  
...  
Keyword(s):  
Atomic Hydrogen ◽  
Molecular Hydrogen ◽  
Theoretical Study ◽  
Reaction Pathway ◽  
Copper Hydride

Theoretical study of deuterium isotope effects on acid–base equilibria under ambient and hydrothermal conditions

RSC Advances ◽  
2015 ◽  
Vol 5 (12) ◽  
pp. 9097-9109 ◽  
Author(s):  
Nelaine Mora-Diez ◽  
Yulia Egorova ◽  
Hart Plommer ◽  
Peter R. Tremaine
Keyword(s):  
Excellent Agreement ◽  
Theoretical Study ◽  
Isotope Effects ◽  
Acid Base ◽  
Hydrothermal Conditions ◽  
Deuterium Isotope Effects ◽  
Calculated Difference

The calculated difference between pKa values in H2O and D2O is in excellent agreement with experiment.

Mechanism of hydration and isomerisation of 4-ethylidene-2,6-di-tert-butyl-2,5-cyclohexadien-1-one. Kinetics, acid-base catalysis and solvent deuterium isotope effects

1979 ◽  
Vol 44 (1) ◽  
pp. 110-122 ◽  
Author(s):  
Jiří Velek ◽  
Bohumír Koutek ◽  
Milan Souček
Keyword(s):  
Aqueous Medium ◽  
Rate Equation ◽  
Kinetic Data ◽  
Isotope Effects ◽  
Base Catalysis ◽  
Quinone Methide ◽  
Reaction Products ◽  
Acid Base ◽  
Deuterium Isotope Effects ◽  
Hydroxybenzyl Alcohol

Competitive hydration and isomerisation of the quinone methide I at 25 °C in an aqueous medium in the region of pH 2.4-13.0 was studied spectrophotometrically. The only reaction products in the studied range of pH are 4-hydroxybenzyl alcohol (II) and 4-hydroxystyrene (III). The form of the overall rate equation corresponds to a general acid-base catalysis. The mechanism of both reactions for three markedly separated pH regions is discussed on the basis of kinetic data and solvent deuterium effect.

Sign in / Sign up

Export Citation Format

Share Document