scholarly journals Reply to the ‘Comment on “The role of electrostatic induction in secondary isotope effects on acidity”’ by C. L. Perrin, New J. Chem., 2015, 39, DOI: 10.1039/C4NJ01887G

2015 ◽  
Vol 39 (2) ◽  
pp. 1522-1524 ◽  
Author(s):  
E. Amitai Halevi
Keyword(s):  
Isotope Effects ◽  
Harmonic Frequencies ◽  
Vibrational Anharmonicity ◽  
Electrostatic Induction

Shifts of harmonic frequencies suffice to explain isotope effects, but it does not follow that vibrational anharmonicity can be neglected.

scholarly journals Comment on “The role of electrostatic induction in secondary isotope effects on acidity” by E. A. Halevi, New J. Chem., 2014, 38, 3840

2015 ◽  
Vol 39 (2) ◽  
pp. 1517-1521 ◽  
Author(s):  
Charles L. Perrin
Keyword(s):  
Isotope Effects ◽  
Electrostatic Induction ◽  
Deuterium Isotope Effects

We reject Halevi's interpretation and reaffirm our conclusion that secondary deuterium isotope effects on acidity are due to n–σ* delocalization.

scholarly journals The role of electrostatic induction in secondary isotope effects on acidity: theory and computational confirmation

2014 ◽  
Vol 38 (8) ◽  
pp. 3840-3852 ◽  
Author(s):  
E. Amitai Halevi
Keyword(s):  
Aqueous Solution ◽  
Gas Phase ◽  
Isotope Effects ◽  
Electrostatic Induction

How well can secondary isotope effects on acidity in aqueous solution be approximated by gas-phase computations on the hydrated components?

The Importance of Anharmonicity of The Vibrational Excited States in Chemical Kinetics

1975 ◽  
Vol 53 (20) ◽  
pp. 3069-3074 ◽  
Author(s):  
Jan Bron
Keyword(s):  
Transition State ◽  
Excited States ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
Vibrational States ◽  
Vibrational Anharmonicity ◽  
Kinetic Isotope ◽  
Large Correction ◽  
Lower Temperature ◽  
Lower Temperature Region

The corrections to rate constants for an harmonicity of vibrational excited states have been evaluated over the temperature range of 200–1100 K. The reaction O2 + X, where X is H or D, has been chosen as the model system. Only the influence of vibrational anharmonicity of the triatomic transition state has been determined. Two geometric shapes for the transition state, bent and isosceles configurations, have been investigated in detail by the bond order method.It is found that the correction can be large, depending upon the geometry and force field of the transition state and the temperature. The magnitude of the correction for anharmonicity of the vibrational excited states depends mainly, at a particular temperature, on the strength of the O—X bond in the transition state. In the case of a large correction, anharmonicity may lead to a nonlinear Arrhenius plot.Because of cancellation effects, the correction for anharmonicity of the excited vibrational states in kinetic isotope effects can be ignored in the lower temperature region. It has also been found that anharmonicity of the vibrational groundstate can explain unexpected large isotope effects.

scholarly journals Role of vibrational anharmonicity in atmospheric radical hydrogen-bonded complexes

2009 ◽  
Vol 11 (30) ◽  
pp. 6377 ◽  
Author(s):  
M. Torrent-Sucarrat ◽  
J. M. Anglada ◽  
J. M. Luis
Keyword(s):  
Vibrational Anharmonicity ◽  
Bonded Complexes ◽  
Hydrogen Bonded

Secondary Kinetic Isotope Effects in Bimolecular Nucleophilic Substitutions. V. The Role of the Solvent in the Reaction Between Methyl Iodide and Pyridine

1972 ◽  
Vol 50 (7) ◽  
pp. 982-985 ◽  
Author(s):  
K. T. Leffek ◽  
A. F. Matheson
Keyword(s):  
Transition State ◽  
Isotope Effects ◽  
Kinetic Isotope Effects ◽  
State Structure ◽  
Transition State Structure ◽  
Initial State ◽  
Nucleophilic Substitutions ◽  
Kinetic Isotope ◽  
Deuterium Isotope Effects

Secondary kinetic deuterium isotope effects are presented for the reaction of methyl-d3 iodide and pyridine in four different solvents. Calculations on mass and moment of inertia change with deuteration in the initial state and an assumed tetrahedral transition state, together with internal rotational effects, are used to rationalize the inverse isotope effects. It is concluded from the variation of the isotopic rate ratio, that the transition state structure varies with solvent.

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