Intrinsic deuterium/proton NMR isotope effects on carbon-13 chemical shifts: dependence on carbon hybridization and substitution

This review outlines methods to investigate the structure of natural products with emphasis on intramolecular hydrogen bonding, tautomerism and ionic structures using NMR techniques. The focus is on 1H chemical shifts, isotope effects on chemical shifts and diffusion ordered spectroscopy. In addition, density functional theory calculations are performed to support NMR results. The review demonstrates how hydrogen bonding may lead to specific structures and how chemical equilibria, as well as tautomeric equilibria and ionic structures, can be detected. All these features are important for biological activity and a prerequisite for correct docking experiments and future use as drugs.

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Hydrogen/Deuterium-Isotope Effects on NMR Chemical Shifts and Symmetry of Homoconjugated Hydrogen-Bonded Ions in Polar Solution

Journal of the American Chemical Society ◽

10.1021/ja0017615 ◽

2000 ◽

Vol 122 (51) ◽

pp. 12878-12879 ◽

Cited By ~ 67

Author(s):

Parwin Schah-Mohammedi ◽

Ilja G. Shenderovich ◽

Carsten Detering ◽

Hans-Heinrich Limbach ◽

Peter M. Tolstoy ◽

...

Keyword(s):

Chemical Shifts ◽

Isotope Effects ◽

Polar Solution ◽

Nmr Chemical Shifts ◽

Hydrogen Deuterium ◽

Deuterium Isotope Effects ◽

Hydrogen Bonded

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Ultrahigh resolution in proton NMR spectra at 500 MHz: two-bond intrinsic chlorine and silicon isotope effects

Journal of the American Chemical Society ◽

10.1021/ja00253a060 ◽

1987 ◽

Vol 109 (19) ◽

pp. 5870-5871 ◽

Cited By ~ 12

Author(s):

Frank A. L. Anet ◽

Max Kopelevich

Keyword(s):

Nmr Spectra ◽

Isotope Effects ◽

Proton Nmr ◽

Silicon Isotope ◽

Ultrahigh Resolution

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Carbon-13/carbon-12 isotope effects on nitrogen-15 chemical shielding in some diamagnetic cyano complexes

Canadian Journal of Chemistry ◽

10.1139/v82-312 ◽

1982 ◽

Vol 60 (17) ◽

pp. 2194-2197 ◽

Cited By ~ 23

Author(s):

Roderick E. Wasylishen

Keyword(s):

Transition Metal ◽

High Field ◽

Chemical Shifts ◽

Isotope Effects ◽

Chemical Shielding ◽

Cyanide Ion ◽

Theoretical Formulation ◽

Metal Cyanides ◽

Shielding Constants ◽

Cyano Complexes

Carbon-13/carbon-12 isotope-induced 15N chemical shifts of 0.06 to 0.10 ppm have been observed for the cyanide ion and several transition metal cyanides. In each case, the 15N resonance of the 13C labelled isotopomers is to high field of that in the corresponding carbon-12 species. The sensitivity of the 15N and 13C shielding constants in the cyanide ion to small changes in the CN bond length are evaluated using the theoretical formulation of Jameson: (∂σ(15N)/∂r)e = −872 ± 160 ppm/Å and (∂σ(13C)/∂r)e = −473 ± 90 ppm/Å. Nitrogen-15 chemical shifts in the metal complexes exhibit basically the same behaviour as do the 13C chemical shifts in these same complexes.

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