The Geometrical Dependence of Experimental and Theoretical Nuclear Spin–Spin Coupling Constants in the 15NH2 Fragment

1973 ◽  
Vol 51 (18) ◽  
pp. 3087-3096 ◽  
Author(s):  
Roderick E. Wasylishen ◽  
T. Schaefer
Keyword(s):  
Benzene Ring ◽  
Nuclear Spin ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Amino Group ◽  
Molecular Orbital Theory ◽  
Orbital Theory ◽  
Spin Coupling Constants ◽  
Experimental Values ◽  
Spin Spin Coupling

Approximate molecular orbital theory at the INDO level of approximation has been used to examine 1J(15N,H) and 2(HNH) in ammonia as a function of the HNH angle. The couplings are very sensitive to the value of the HNH angle in the range from 110 to 120°. The computed trends are compared with those observed in other compounds containing the 15NH2 fragment. The signs and magnitudes of 1J(15N,H) and 2J(HNH) have been measured for 2-aminoacetophenone at temperatures where the amino protons are nonequivalent. The observed and calculated results suggest that the amino group lies in the plane of the benzene ring. In aniline the magnitude of 2J(HNH) lies between 1 and 2 Hz and on the basis of the trends in the calculated and experimental values the sign can be confidently taken as negative.

Carbon-13, proton spin–spin coupling constants in some 4-substituted isothiazoles and related heterocyclics

1977 ◽  
Vol 55 (4) ◽  
pp. 619-624 ◽  
Author(s):  
Roderick E. Wasylishen ◽  
Harold M. Hutton
Keyword(s):  
Perturbation Theory ◽  
Nuclear Spin ◽  
Proton Spin ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Molecular Orbital Theory ◽  
Orbital Theory ◽  
Spin Coupling Constants ◽  
Semi Empirical ◽  
Spin Spin Coupling

Carbon-13, proton nuclear spin–spin coupling constants have been measured for a number of 4-substituted isothiazoles. The observed values are compared with those measured in other heterocyclic systems and those calculated in the parent and related heterocyclics using finite perturbation theory and semi-empirical molecular orbital theory at the CNDO/2 and INDO levels of approximation.

scholarly journals An efficient DFT method of predicting the one-, two- and three-bond indirect spin–spin coupling constants involving a fluorine nucleus in fluoroalkanes

RSC Advances ◽  
2016 ◽  
Vol 6 (86) ◽  
pp. 82783-82792 ◽  
Author(s):  
Adam Gryff-Keller ◽  
Przemysław Szczeciński
Keyword(s):  
Nuclear Spin ◽  
Dft Method ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Fluorine Nucleus ◽  
Spin Coupling Constants ◽  
Experimental Values ◽  
The One ◽  
Spin Spin Coupling

The values of the indirect nuclear spin–spin coupling constants for a series of aliphatic fluorocompounds have been calculated using DFT-based methods and compared with the experimental values of these parameters.

An increased internal rotational barrier in thiophenol caused by meta substituents

1985 ◽  
Vol 63 (9) ◽  
pp. 2471-2475 ◽  
Author(s):  
Ted Schaefer ◽  
James D. Baleja ◽  
Glenn H. Penner
Keyword(s):  
Molecular Orbital ◽  
Long Range ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Molecular Orbital Theory ◽  
Mo Calculations ◽  
Orbital Theory ◽  
Spin Coupling Constants ◽  
Internal Barriers ◽  
Spin Spin Coupling

The twofold internal barriers to rotation about the C—S bond in 3,5-diX-thiophenols were determined in solution from long-range spin–spin coupling constants. They are 3.4, 4.85, 5.3, 6.45, and 7.25 ± 10% kJ/mol for X = H, CH3, OCH3, F, and Cl, respectively. In 3,5-dichloro-4-hydroxythiophenol, V2 is −0.8 kJ/mol as compared to −1.9 kJ/mol in 4-methoxythiophenol. The para substituent here dominates. The observed barriers are in rough agreement with arguments based on perturbation molecular orbital theory and with MO calculations of changes in the barrier caused by substituents. The computed values appear as nearly pure twofold barriers with very small fourfold components.

Molecular orbital theory of nuclear spin coupling constants

1964 ◽  
Vol 8 (1) ◽  
pp. 1-18 ◽  
Author(s):  
J.A. Pople ◽  
D.P. Santry
Keyword(s):  
Molecular Orbital ◽  
Nuclear Spin ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Molecular Orbital Theory ◽  
Orbital Theory ◽  
Spin Coupling Constants

Vibrational and thermal averaging of the indirect nuclear spin-spin coupling constants of CH4, SiH4, GeH4 and SnH4

1997 ◽  
Vol 91 (5) ◽  
pp. 897-907 ◽  
Author(s):  
SHEELA KIRPEKAR ◽  
THOMAS ENEVOLDSEN ◽  
JENS ODDERSHEDE ◽  
WILLIAM RAYNES
Keyword(s):  
Nuclear Spin ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling

High‐Level Electron Correlation of the Indirect Nuclear Spin‐Spin Coupling Constants in Some Small Diboranes and Lithium‐Doped Diboranes

2021 ◽  
Vol 6 (22) ◽  
pp. 5451-5465
Author(s):  
Antonio P. Santos Neto ◽  
Roberto Rivelino ◽  
Gabriel I. Pagola ◽  
Patricio F. Provasi
Keyword(s):  
Electron Correlation ◽  
Nuclear Spin ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Spin Coupling Constants ◽  
High Level ◽  
Spin Spin Coupling
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