Hydrogen abstractions from methyl groups by atomic oxygen. Kinetic isotope effects calculated from MNDO/UHF results and an assessment of their applicability to monooxygenase-dependent hydroxylations

1983 ◽  
Vol 87 (6) ◽  
pp. 1081-1085 ◽  
Author(s):  
Andrew T. Pudzianowski ◽  
Gilda H. Loew
Keyword(s):  
Atomic Oxygen ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Methyl Groups ◽  
Kinetic Isotope

DEUTERIUM KINETIC ISOTOPE EFFECTS: V TEMPERATURE DEPENDENCE OF β-DEUTERIUM EFFECTS IN WATER SOLVOLYSIS OF ISOPROPYL COMPOUNDS

1961 ◽  
Vol 39 (10) ◽  
pp. 1989-1994 ◽  
Author(s):  
K. T. Leffek ◽  
R. E. Robertson ◽  
S. E. Sugamori
Keyword(s):  
Temperature Dependence ◽  
Isotope Effect ◽  
Isotope Effects ◽  
Zero Point ◽  
Kinetic Isotope Effects ◽  
Methyl Groups ◽  
Deuterium Isotope Effect ◽  
Point Energy ◽  
Kinetic Isotope ◽  
Enthalpy Of Activation

The secondary β-deuterium isotope effect (kH/kD) has been measured over a range of temperature for the water solvolysis reactions of isopropyl methanesulphonate, p-toluenesulphonate, and bromide. In these cases the isotope effect is due to a difference in entropies of activation of the isotopic analogues rather than a difference in the enthalpies of activation. It is suggested that the observed isotope effect is due to internal rotational effects of the methyl groups in the isopropyl radical, and the lack of an isotope effect on the enthalpy of activation is accounted for by a cancellation of an effect from this source and one from zero-point energy.

Secondary Isotope Effects on the Ionization of 2-Nitropropane

1974 ◽  
Vol 52 (10) ◽  
pp. 1889-1896 ◽  
Author(s):  
A. J. Kresge ◽  
D. A. Drake ◽  
Y. Chiang
Keyword(s):  
Aqueous Solution ◽  
Isotope Effect ◽  
Kinetic Isotope Effect ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Acid Dissociation ◽  
Methyl Groups ◽  
Anomalous Effect ◽  
Hydroxide Ion ◽  
Kinetic Isotope

The equilibrium isotope effect on the acid dissociation of 2-nitropropane in wholly aqueous solution at 25° was found to be KH/KD = 1.23 ± 0.03 for complete deuteration of both methyl groups; the kinetic isotope effect for reaction of the same substrate with hydroxide ion, kH/kD = 1.09 ± 0.01; and the kinetic isotope effect for reaction with tris-(hydroxymethyl)-methylamine, kH/kD = 1.10 ± 0.01; both of the latter also refer to wholly aqueous solution at 25° and are for complete deuteration of both methyl groups. It is shown that the equilibrium isotope effect is largely, and the kinetic isotope effects probably partly, hyper conjugative in origin, thus supporting a hyper conjugative explanation of the anomalous effect of methyl groups on nitroalkane ionization.

Primary and secondary kinetic isotope effects in proton (H+/D+) and chloronium ion (35Cl+/37Cl+) affinities

2001 ◽  
Vol 36 (10) ◽  
pp. 1140-1148 ◽  
Author(s):  
F�bio Cesar Gozzo ◽  
Marcos N. Eberlin
Keyword(s):  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Kinetic Isotope

Theoretical Simulations of Heavy-Atom Kinetic Isotope Effects in Aliphatic Claisen Rearrangement

2020 ◽  
Vol 124 (51) ◽  
pp. 10678-10686
Author(s):  
Yuqing Xu ◽  
Kin-Yiu Wong ◽  
Meishan Wang ◽  
Desheng Liu ◽  
Wenkai Zhao ◽  
...  
Keyword(s):  
Claisen Rearrangement ◽  
Isotope Effects ◽  
Heavy Atom ◽  
Kinetic Isotope Effects ◽  
Kinetic Isotope ◽  
Theoretical Simulations

Direct dynamics calculations of reaction rate and kinetic isotope effects in enzyme catalysed reactions

2002 ◽  
Vol 122 ◽  
pp. 223-242 ◽  
Author(s):  
Gary Tresadern ◽  
Sara Nunez ◽  
Paul F. Faulder ◽  
Hong Wang ◽  
Ian H. Hillier ◽  
...  
Keyword(s):  
Reaction Rate ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Direct Dynamics ◽  
Kinetic Isotope

Interpretation of Transient-State Kinetic Isotope Effects†

Biochemistry ◽  
1996 ◽  
Vol 35 (1) ◽  
pp. 83-88 ◽  
Author(s):  
Harvey F. Fisher ◽  
Swapan K. Saha
Keyword(s):  
Isotope Effects ◽  
Transient State ◽  
Kinetic Isotope Effects ◽  
Kinetic Isotope ◽  
State Kinetic
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