Aziridine Nitrogen Inversion by Dynamic NMR: Activation Parameters in a Fused Bicyclic Structure

2013 ◽  
Vol 78 (22) ◽  
pp. 11623-11626 ◽  
Author(s):  
Denisse de Loera ◽  
Fang Liu ◽  
K. N. Houk ◽  
Miguel A. Garcia-Garibay
Keyword(s):  
Activation Parameters ◽  
Dynamic Nmr ◽  
Nitrogen Inversion ◽  
Bicyclic Structure

Conformational studies by dynamic NMR. IX. Activation parameters for the barrier to C-N rotation in N,N-dimethylbenzamidine : a correction

1977 ◽  
Vol 18 (12) ◽  
pp. 1079-1080 ◽  
Author(s):  
Lodovico Lunazzi ◽  
Alessandro Dondoni ◽  
Gaetano Barbaro ◽  
Dante Macciantelli
Keyword(s):  
Activation Parameters ◽  
Dynamic Nmr ◽  
Conformational Studies

Determination of the activation parameters of permanent allylic rearrangement in allyl- and methallylboranes and in 1,1-bis(dipropylborylmethyl)ethylene by dynamic NMR spectroscopy

1992 ◽  
Vol 424 (2) ◽  
pp. 127-132 ◽  
Author(s):  
Yu.N. Bubnov ◽  
M.E. Gurskii ◽  
I.D. Gridnev ◽  
A.V. Ignatenko ◽  
Yu.A. Ustynyuk ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Activation Parameters ◽  
Dynamic Nmr ◽  
Allylic Rearrangement ◽  
Dynamic Nmr Spectroscopy

Restricted Nitrogen Inversion in N-Methylpolyhalobenz-7-azanorbornadienes. 1H Dynamic NMR Studies and Molecular Conformation Trapping

1995 ◽  
Vol 60 (1) ◽  
pp. 268-271 ◽  
Author(s):  
C. Hackett Bushweller ◽  
Jay H. Brown ◽  
Christine M. DiMeglio ◽  
Gordon W. Gribble ◽  
Jefferson T. Eaton ◽  
...  
Keyword(s):  
Molecular Conformation ◽  
Dynamic Nmr ◽  
Nmr Studies ◽  
Nitrogen Inversion

Dynamic NMR spectroscopy of 2,2′-dimethyl-1-picrylhydrazine in various solvents

2006 ◽  
Vol 84 (12) ◽  
pp. 1648-1657 ◽  
Author(s):  
K C Brown ◽  
M El-Bermani ◽  
Y Upadrashta ◽  
J A Weil
Keyword(s):  
Conformational Changes ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Activation Parameters ◽  
Detailed Comparison ◽  
Liquid Solution ◽  
Molecular Orbital Calculations ◽  
Dynamic Nmr ◽  
Hindered Rotation ◽  
H Nmr

We have studied the 1H NMR spectra of 2,2′-dimethyl-1-(2,4,6-trinitrophenyl)hydrazine at 300 and 500 MHz in seven liquid solvents, with a view to learning details of the internal conformational changes taking place as a function of temperature and of the solvent. These molecules in liquid solution occur as interconverting enantiomorphic pairs (atropisomers). Advanced techniques for obtaining the correct activation energies and pseudo-thermodynamic parameters have been utilized, and these parameters are listed and discussed. Our results point to a transformation between the pair of atropisomers that is not quite as complicated as one might have encountered in that the solvent does not affect ΔG‡ in any major fashion. Molecular orbital calculations clarified some of the chemical shifts observed for both 1H and 13C. One goal of this study was to enable a detailed comparison with similar results available for 2,2′-diphenyl-1-(2,4,6-trinitrophenyl)hydrazine.Key words: dynamic NMR, dimethylpicrylhydrazine, hindered rotation, atropisomers, activation parameters.

ChemInform Abstract: Determination of the Activation Parameters of Permanent Allylic Rearrangement in Allyl- and Methallylboranes and in 1,1-Bis( dipropylborylmethyl)ethylene by Dynamic NMR Spectroscopy.

ChemInform ◽  
2010 ◽  
Vol 23 (17) ◽  
pp. no-no
Author(s):  
YU. N. BUBNOV ◽  
M. E. GURSKII ◽  
I. D. GRIDNEV ◽  
A. V. IGNATENKO ◽  
YU. A. USTYNYUK ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Activation Parameters ◽  
Dynamic Nmr ◽  
Allylic Rearrangement ◽  
Dynamic Nmr Spectroscopy

Nitrogen inversion and N–O bond rotation processes in di-and tri-substituted hydroxylamines. A dynamic NMR study

1996 ◽  
pp. 1479-1483 ◽  
Author(s):  
Sk. Asrof Ali ◽  
Azfar Hassan ◽  
Mohammed I. M. Wazeer
Keyword(s):  
Dynamic Nmr ◽  
Bond Rotation ◽  
Nitrogen Inversion ◽  
Nmr Study

Phenylfluorophosphoranes: axial–equatorial fluorine exchange in RC6H4PF3H and intermolecular exchange in the PhPF2(H)OMe–MeOH–base system

1990 ◽  
Vol 68 (3) ◽  
pp. 488-491 ◽  
Author(s):  
Leonard J. Kruczynski ◽  
Alberta E. Lemire ◽  
Kirk Marat ◽  
Alexander F. Janzen
Keyword(s):  
Shape Analysis ◽  
Ligand Exchange ◽  
Activation Parameters ◽  
Base System ◽  
Dynamic Nmr ◽  
Nmr Spectrum ◽  
First Order ◽  
H Nmr ◽  
Line Shape Analysis ◽  
Nmr Study

Activation parameters for axial–equatorial fluorine exchange in arylfluorophosphoranes RC6H4PF3H, where R = o-CF3, m-CF3, p-CF3, m-CH3, were studied by the dynamic nmr technique: [Formula: see text] varied between 53 and 56 kJ mol−1.The synthesis of difluoromethoxyphenylphosphorane, PhPF2(H)OMe, from PhPF2 and MeOH is catalyzed by small amounts of Et3N, pyridine, PhPF3H, or HF. Rapid intermolecular ligand exchange occurs in PhPF2(H)OMe after addition of methanol and a base such as triethylamine or pyridine. Under these conditions, exchange of fluorine, hydrogen, and methoxy ligands occurs, as shown by 1H, 19F, and 31P nmr. From a line shape analysis of the 31P{1H} nmr spectrum, the rate of P—F cleavage was found to be first order (1.17 ± 0.2) in Et3N concentration, with [Formula: see text] = 50 kJ mol−1 and ΔS# = −67 J mol−1 deg−1.An equilibrium constant of 1.8 at 25 °C was found for the reaction of PhPF2(H)OMe with PhPF2.Keywords: axial–equatorial fluorine exchange in RC6H4PF3H intermolecular exchange in the PhPF2(H)OMe–MeOH–base system; 31P and 19F nmr study of ligand exchange in phosphoranes.

scholarly journals Dynamic NMR Study of Bond Rotational Activation Parameters in Micelles

2000 ◽  
Author(s):  
Dietmar Leitner
Keyword(s):  
Activation Parameters ◽  
Dynamic Nmr ◽  
Nmr Study
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