## Abstract Geminal ^15^N^13^C coupling constants have been measured in a series of ^15^N‐enriched 1‒phenyl‒3,5‒dialkyl‐substituted pyrazoles. The importance of the orientation of the nitrogen lone‐pair in determining the magnitude of ^2^__J__(^15^N^13^C) values is reflected in the enhanced coupli
The stereochemical dependence of the vicinal 13C14N coupling constant as a constitutional probe
✍ Scribed by Ludo A. Valckx; Frans A. M. Borremans; Chris E. Becu; Robert H. K. De Mar; Marc. J. O. Anteunis
- Publisher
- John Wiley and Sons
- Year
- 1979
- Tongue
- English
- Weight
- 389 KB
- Volume
- 12
- Category
- Article
- ISSN
- 0749-1581
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✦ Synopsis
Abstract
The magnitudes of ^13^C^14^N coupling constants have been measured in 12 rigid or anancomeric (biased) tetraalkylammonium iodides. The one‐bond coupling is typical for the degree of substitution of the carbon atom and the geminal coupling is very small. Vicinal couplings depend on the dihedral angle and other factors.
📜 SIMILAR VOLUMES
## Abstract A series of alicyclic compounds with dihedral angles of 0°, 60°, 90°, 120° and 180° between a ^13^C‐labelled carbon atom and a carbon atom separated by three bonds from the label has been synthesized. The vicinal ^13^C^13^C spin coupling constants were measured, and from the results a K
The dependence of three-bond "GUC couplings of cis-butane and cis-butene on the valence angle, the torsional angle of the methyl groups and methyl and methylene substituents is discussed on the basis of INDO-SCPT calculations. The results support the interpretation of the experimental couplings betw
## Abstract The one‐bond coupling constant ^1^__J__ ^13^CH for the halogenated carbon in α‐halogenocyclohexanones is more important when the CH bond is in the equatorial then in the axial position. When a conformational equilibrium is present, the resulting coupling is a linear function of the eq
## Abstract The first successful observation of the vicinal ^15^N,^13^C spin‐coupling constants in a series of amino acids, comprising Val, Ile, Leu and Thr, in which the α‐nitrogens are fully replaced with ^15^N, is described. A Karplus‐type dihedral‐angle dependence was noted for the coupling con
The complete analysis of the 'H NMR spectra of [ (C,Me,)lr(glycinate)CI] and [ (C,Me,)Ir(N-methyl-g1ycinate)Clj provide information for the conformational analysis of the five-membered N-C-C-0-Ir ring. A Karplus relationship has been established for these metallacycles [ 3J(H,H) = 8.9 cos' 4 -1.0 c