Restricted carbon–nitrogen bond rotation in some ureas, thioureas, and thiuronium salts

1973 ◽  
pp. 2162-2165 ◽  
Author(s):  
Peter Hanson ◽  
David A. R. Williams
Keyword(s):  
Bond Rotation ◽  
Nitrogen Bond

A structural and carbon-nitrogen bond rotation study of N,N,N',N',2,2-hexamethylpropanediamide

1983 ◽  
Vol 36 (9) ◽  
pp. 1865 ◽  
Author(s):  
SF Lincoln ◽  
AM Hounslow ◽  
NJ Maeji ◽  
TW Hambley ◽  
MR Snow ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Solid State ◽  
Kinetic Parameters ◽  
Methyl Groups ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bond Rotation ◽  
Nitrogen Bonds ◽  
Rotation Study ◽  
Nitrogen Bond

The molecular structure of N,N,N',N',2,2-hexamethylpropanediamide has been determined in the solid state by X-ray diffraction methods. The structure of Me2NCOCMe2CONMe2 may be broadly described as two planar Me2NCO entities intersecting at the tetrahedral -CMe2- site. The angle between the normals to the two Me2NCO planes is 104.6�, and the two oxygen atoms are disposed outwards from the molecule and away from each other. Proton (270-MHz) n.m.r. studies yield k(320 K) 32.0 � 3.2 s-1, ΔH‡ 69.5 � 0.4 kJ mol-1 and ΔS‡ 0.6 � 1.1 J K-1 mol-1 for rotation of the N-methyl groups about the carbon-nitrogen bonds in CD3NO2 solution. Similar magnitudes for the kinetic parameters characterizing this process are obtained in CDCl3, and CD3CN solutions.

The Barrier to Rotation About the N—N Bond in N-Nitrosamines as Determined by Nuclear Magnetic Resonance Total Line Shape Analysis

1974 ◽  
Vol 52 (17) ◽  
pp. 3028-3036 ◽  
Author(s):  
J. D. Cooney ◽  
S. K. Brownstein ◽  
J. W. ApSimon
Keyword(s):  
Shape Analysis ◽  
Line Shape ◽  
Energy Barrier ◽  
Activation Parameters ◽  
Substantial Contribution ◽  
Resonance Structure ◽  
Bond Rotation ◽  
Line Shape Analysis ◽  
Bond Character ◽  
Nitrogen Bond

The energy barrier to internal N—N bond rotation in five cyclic and two bicyclic N-nitrosamines [Formula: see text]has been determined using high temperature 100 MHz n.m.r. spectroscopy. A substantial contribution from the ionic resonance structure of [Formula: see text] produces considerable double bond character in the nitrogen–nitrogen bond and a concomitant increase in the rotational barrier about the N—N bond. The molecules were examined in the[Formula: see text]liquid state and had ring sizes varying from five to nine atoms. The Arrhenius and Eyring activation parameters for the energy barrier were determined using total line shape analysis and the intensity ratio approximation method. The energy barrier to N—N bond rotation was found to range from 23–29 kcal/mol depending on the molecular structure and the solvent.

Photoinduced Sulfur–Nitrogen Bond Rotation and Thermal Nitrogen Inversion in Heterocumulene OSNSO

2018 ◽  
Vol 140 (4) ◽  
pp. 1231-1234 ◽  
Author(s):  
Zhuang Wu ◽  
Ruijuan Feng ◽  
Jian Xu ◽  
Yan Lu ◽  
Bo Lu ◽  
...  
Keyword(s):  
Bond Rotation ◽  
Nitrogen Inversion ◽  
Nitrogen Bond

CARBON-NITROGEN BOND ROTATION IN A DITHIOCARBAMATO COMPLEX OF RHODIUM(III)

1984 ◽  
Vol 13 (4) ◽  
pp. 321-324 ◽  
Author(s):  
B. M. Mattson ◽  
A. E. Madera ◽  
M. C. Palazzotto
Keyword(s):  
Bond Rotation ◽  
Nitrogen Bond
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