Chemical Shifts and Electron Densities in Nitrogen Heterocyclic Molecules

1965 ◽  
Vol 42 (8) ◽  
pp. 2658-2670 ◽  
Author(s):  
A. H. Gawer ◽  
B. P. Dailey
Keyword(s):  
Chemical Shifts ◽  
Electron Densities ◽  
Heterocyclic Molecules ◽  
Nitrogen Heterocyclic

Effects of protonation on electron densities in nitrogen heterocyclic molecules

Tetrahedron ◽  
1967 ◽  
Vol 23 (6) ◽  
pp. 2513-2521 ◽  
Author(s):  
W. Adam ◽  
A. Grimison ◽  
G. Rodríguez
Keyword(s):  
Electron Densities ◽  
Heterocyclic Molecules ◽  
Nitrogen Heterocyclic

Correlation of the chemical shifts with ?-electron densities in mono-derivatives of benzene, pyridine, and pyrazine

1968 ◽  
Vol 17 (5) ◽  
pp. 951-958
Author(s):  
G. G. Dvoryantseva ◽  
V. P. Lezina ◽  
V. F. Bystrov ◽  
T. N. Ul'yanova ◽  
G. P. Syrova ◽  
...  
Keyword(s):  
Chemical Shifts ◽  
Electron Densities ◽  
Derivatives Of

Elektronendichte und chemische Verschiebung der Styryldiazin- und Diazaphenanthrenprotonen / Electrondensity and Proton Chemical Shift of Styryldiazines and Diazaphenanthrenes

1972 ◽  
Vol 27 (2) ◽  
pp. 310-319
Author(s):  
H.-H. Perkampus ◽  
Th. Bluhm ◽  
J. Knop
Keyword(s):  
Ring Current ◽  
Chemical Shifts ◽  
Lone Pair ◽  
Current Effect ◽  
Electron Densities ◽  
Paramagnetic Effect ◽  
Nitrogen Lone Pair ◽  
Chemische Verschiebung ◽  
Lone Pair Electrons ◽  
Proton Chemical Shifts

AbstractProton chemical shifts in styryldiazines and diazaphenanthrenes linearly correlate with SCF-π-electron densities of the attached carbon atom and with the electron densities of the hydrogen atom (calculated by the CNDO/2 method). The observed deviations from linearity are discussed in terms of ring current effect, steric effects and the paramagnetic effect of the nitrogen lone pair electrons. An appreciable weakening of ring current is found for diazaphenanthrenes with two adjacent N-atoms. Under the same condition the paramagnetic effect on ortho-hydrogens is increased.

Calcul des déplacements chimiques par la méthode des perturbations finies au niveau INDO avec GIAO et approximation de London. I. 13C et 1H

1982 ◽  
Vol 60 (8) ◽  
pp. 957-969 ◽  
Author(s):  
E. Vauthier ◽  
S. Odiot ◽  
F. Tonnard
Keyword(s):  
Perturbation Method ◽  
Chemical Shifts ◽  
Average Precision ◽  
Electron Densities ◽  
Screening Constant ◽  
First Order ◽  
Finite Perturbation

A formalism for the calculation of σ in the finite perturbation method is developed by keeping hermitian the first order perturbed matrix in B. The σ formalism is separated into mono, di, and triatomic terms, and the importance of the electron densities of neighboring and remote bonds is shown. 13C chemical shifts depend only slightly on the remote bonds in contrast to those for 1H. A calculation of the screening constant for a series of 16 sp and sp2 carbons gives an average precision of 5 ppm for the 13C nuclei. [Journal Translation]

Proton chemical shifts and electron densities

1962 ◽  
Vol 34 ◽  
pp. 18 ◽  
Author(s):  
B. P. Dailey ◽  
Albert Gawer ◽  
W. C. Neikam
Keyword(s):  
Chemical Shifts ◽  
Electron Densities ◽  
Proton Chemical Shifts

The radio spectra of planar aromatic heterocycles: how to quantify and predict the negative inertial defects

2017 ◽  
Vol 19 (13) ◽  
pp. 8970-8976 ◽  
Author(s):  
Michaela K. Jahn ◽  
Jens-Uwe Grabow ◽  
Michael J. Travers ◽  
Dennis Wachsmuth ◽  
Peter D. Godfrey ◽  
...  
Keyword(s):  
Interstellar Medium ◽  
Aromatic Heterocycles ◽  
Heterocyclic Molecules ◽  
Aromatic Systems ◽  
Nitrogen Heterocyclic

The simplest tricyclic aromatic nitrogen heterocyclic molecules 5,6-benzoquinoline and 7,8-benzoquinoline are possible candidates for detection of aromatic systems in the interstellar medium.

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