Empirical analysis of vicinal proton-proton spin-spin coupling constants from the classic and modified Karplus equations in the ?-piperidone series

1992 ◽  
Vol 41 (7) ◽  
pp. 1207-1213
Author(s):  
A. �. Aliev ◽  
A. A. Sinitsyna
Keyword(s):  
Empirical Analysis ◽  
Proton Spin ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Proton Proton ◽  
Vicinal Proton ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling

Exo-exo and endo-endo vicinal proton spin-spin coupling constants in norbornane and norbornene. An IPPP-CLOPPA analysis

1991 ◽  
Vol 12 (2) ◽  
pp. 141-146 ◽  
Author(s):  
C. N. Cavasotto ◽  
C. G. Giribet ◽  
M. C. Ruiz de Azúa ◽  
R. H. Contreras
Keyword(s):  
Proton Spin ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Vicinal Proton ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling

The Proton–Proton and Proton–Carbon-13 Spin–Spin Coupling Constants in 1,3-Dioxole and Bis-1,3-dioxolyl. Conformational Dependence

1975 ◽  
Vol 53 (18) ◽  
pp. 2734-2741 ◽  
Author(s):  
Ted Schaefer ◽  
Kalvin Chum ◽  
David McKinnon ◽  
M. S. Chauhan
Keyword(s):  
Double Resonance ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Dihedral Angles ◽  
Proton Proton ◽  
Proton Coupling ◽  
Vicinal Proton ◽  
Karplus Relationship ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling

The carbon-13 satellite peaks in the proton magnetic resonance spectra of 1,3-dioxole and bis-1,3-dioxolyl are analyzed under single and double resonance conditions to yield the signs and magnitudes of proton–proton coupling constants over three, four, and five bonds, and of proton–carbon-13 coupling constants over one, two, and three bonds. The conformational behavior of bis-1,3-dioxolyl contrasts sharply with that of analogous sym-tetrasubstituted ethane derivatives. It is indicated that the two-bond proton–carbon-13 coupling in the ethanic fragment can be used for conformational analysis in a manner similar to vicinal proton–proton couplings. The vicinal three-bond proton–carbon-13 couplings are given for dihedral angles of 180 and 120° and their relative magnitudes are as expected from a Karplus relationship. The two-bond proton–carbon-13 coupling in the olefinic fragment is, at 20.0 Hz, the largest coupling known for such a bond.

scholarly journals Glycosaminoglycan Monosaccharide Blocks Analysis by Quantum Mechanics, Molecular Dynamics, and Nuclear Magnetic Resonance

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Sergey A. Samsonov ◽  
Stephan Theisgen ◽  
Thomas Riemer ◽  
Daniel Huster ◽  
M. Teresa Pisabarro
Keyword(s):  
Molecular Dynamics ◽  
Dihedral Angle ◽  
Chemical Shifts ◽  
Proton Spin ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Proton Proton ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling ◽  
The Impact

Glycosaminoglycans (GAGs) play an important role in many biological processes in the extracellular matrix. In a theoretical approach, structures of monosaccharide building blocks of natural GAGs and their sulfated derivatives were optimized by a B3LYP6311ppdd//B3LYP/6-31+G(d) method. The dependence of the observed conformational properties on the applied methodology is described. NMR chemical shifts and proton-proton spin-spin coupling constants were calculated using the GIAO approach and analyzed in terms of the method's accuracy and sensitivity towards the influence of sulfation, O1-methylation, conformations of sugar ring, andωdihedral angle. The net sulfation of the monosaccharides was found to be correlated with the1H chemical shifts in the methyl group of the N-acetylated saccharides both theoretically and experimentally. Theωdihedral angle conformation populations of free monosaccharides and monosaccharide blocks within polymeric GAG molecules were calculated by a molecular dynamics approach using the GLYCAM06 force field and compared with the available NMR and quantum mechanical data. Qualitative trends for the impact of sulfation and ring conformation on the chemical shifts and proton-proton spin-spin coupling constants were obtained and discussed in terms of the potential and limitations of the computational methodology used to be complementary to NMR experiments and to assist in experimental data assignment.

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