Picosecond Dynamics of Intermolecular Proton and Deuteron Transfer between Benzophenone andN,N-Dimethylaniline

1996 ◽  
Vol 100 (50) ◽  
pp. 19412-19416 ◽  
Author(s):  
Jens Dreyer ◽  
Kevin S. Peters
Keyword(s):  
Deuteron Transfer

Isotope effects and activation parameters for the proton transfer reaction from 1-(4-nitrophenyl)-1-nitroethane to free anions and ion pairs of cesium n-propoxide in n-propanol solvent

1986 ◽  
Vol 64 (6) ◽  
pp. 1021-1025 ◽  
Author(s):  
Arnold Jarczewski ◽  
Grzegorz Schroeder ◽  
Przemyslaw Pruszynski ◽  
Kenneth T. Leffek
Keyword(s):  
Proton Transfer ◽  
Rate Constants ◽  
Isotope Effects ◽  
Ion Pairs ◽  
Activation Parameters ◽  
Solvation Shell ◽  
Ion Pair ◽  
Initial State ◽  
Free Ion ◽  
Deuteron Transfer

Rate constants for the proton and deuteron transfer from 1-(4-nitrophenyl)-1-nitroethane to cesium n-propoxide in n-propanol have been measured under pseudo-first-order conditions with an excess of base for four temperatures between 5 and 35 °C. Using literature values of the fraction of cesium n-propoxide ion pairs that are dissociated into free ions, separate second-order rate constants for the proton and deuteron transfer to the ion pair and to the free ion have been calculated. The cesium n-propoxide ion pair is about 2.8 times more reactive than the free n-propoxide ion. The primary kinetic isotope effects for the two reactions are the same (kH/kD = 6.1–6.3 at 25 °C) within experimental error. The enthalpy of activation is smaller for the ion-pair reaction and the entropy of activation more negative than for the free-ion reaction. For proton transfer, ΔH±ion pair = 8.3 ± 0.2 kcal mol−1, ΔH±ion = 9.6 ± 1.0 kcal mol−1, ΔS±ion pair = −12.3 ± 0.6 cal mol−1 deg−1, ΔS±ion = −10.1 ± 3.4 cal mol−1 deg−1. The greater reactivity of the ion pair relative to the free ion is interpreted in terms of the weaker solvation shell of the ion pair in the initial state.

Influence of coupling of excited states and of deuteron transfer on fusion reactions induced by 6,7Li on 64Ni, 152Sm and 209Bi targets

2019 ◽  
Vol 990 ◽  
pp. 149-161
Author(s):  
Neha Rani ◽  
Pardeep Singh ◽  
Monika Singh ◽  
Ravinder Kumar ◽  
Rajiv Kumar ◽  
...  
Keyword(s):  
Excited States ◽  
Fusion Reactions ◽  
Deuteron Transfer

The kinetics of proton and deuteron transfer from 4-nitrophenylnitromethane and l-(4-nitrophenyl)-l-nitroethane to 2,7-dimethoxy-l,8-bis(dimethylamino)naphthalene in acetonitrile solvent

1981 ◽  
Vol 59 (21) ◽  
pp. 3034-3038 ◽  
Author(s):  
Kenneth T. Leffek ◽  
Przemyslaw Pruszynski
Keyword(s):  
Isotope Effect ◽  
Reaction Rate ◽  
Significant Contribution ◽  
Reaction Parameters ◽  
Deuterium Isotope Effect ◽  
First Order ◽  
Enthalpy Of Activation ◽  
Deuteron Transfer ◽  
Slow Dissociation ◽  
Kinetics Of

4-Nitrophenylnitromethane reacts with 2,7-dimethoxy-1,8-bis(dimethylamino)naphthalene in acetonitrile in a bimolecular proton transfer, which shows a primary deuterium isotope effect, kH/kD = 12.2 at 25 °C. The large isotope effect on the enthalpy of activation, (ΔHD≠ – ΔHH≠) = 4.6 ± 0.3 kcal mol−1 is consistent with a significant contribution of proton tunnelling to the reaction rate of the protium substrate.The analogous reaction of 1-(4-nitrophenyl)-1-nitroethane with the same base in acetonitrile gives contrasting kinetics and reaction parameters. The reaction is first order, showing no dependence on base concentration. While the isotope effect kH/kD = 9.3 at 25 °C, the enthalpy of activation difference (ΔHD≠ – ΔHH≠) is only 0.5 ± 0.1 kcal mol−1. It is concluded that the 1-(4-nitrophenyl)-1-nitroethane undergoes a slow dissociation, with a very small dissociation constant, followed by a fast association with the base to yield the carbanion ion-pair.

Chemische Reaktionen des O--Ions im Massenspektrometer

1967 ◽  
Vol 22 (6) ◽  
pp. 961-965 ◽  
Author(s):  
K. Jäger ◽  
M. Simic ◽  
A. Henglein
Keyword(s):  
Proton Transfer ◽  
Atom Transfer ◽  
Chemische Reaktionen ◽  
Fast Reactions ◽  
Deuteron Transfer

Fast reactions of 0- with water, various alcohols, diethylether, acetone, c-hexane, c-hexene, benzene and toluene have been observed. The following types of reactions which often compete in these systems have been found: a) Η-atom transfer (such as CH3OD+O- → OH-+CH2+CH2OD), b) Proton (deuteron) transfer (such as CH3OH+O-→ CH3O–+OH, and CH3OD+O-→ CH3O-+OD), c) H2+-transfer [such as (CH33)2CO+O- → C3H4O-+H2O], d) dissociative proton transfer (such as i-C3H7OH+O- → C2H3O-+OH+CH4 or C3H5O-+OH+H2), e) dissociative addition (such as C6H6 → C6H5O-+H).

Sign in / Sign up

Export Citation Format

Share Document