## 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
13C NMR: Stereochemical dependence of the one-bond coupling constant 1J13CH in α-halogenoketones
✍ Scribed by J. Cantacuzene; R. Jantzen; M. Tordeux; C. Chachaty
- Publisher
- John Wiley and Sons
- Year
- 1975
- Tongue
- English
- Weight
- 135 KB
- Volume
- 7
- Category
- Article
- ISSN
- 0749-1581
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✦ Synopsis
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 equilibrium constant.
📜 SIMILAR VOLUMES
## Abstract ^1^__J__(^13^CH) and ^2^__J__(^13^CH) involving the aldehydic proton in __ortho__‐alkylbenzaldehydes have been examined for evidence of a hyperconjugative contribution from the aromatic π‐electrons. The expected hyperconjugative effect is obscured by changes in the coupling constants re
## Abstract ^13^C __T__~1ρ~ values measured for isobutylamine, diethylamine, pyrrolidine, piperidine and triethylamine yield one‐bond ^14^N^13^C coupling constants and ^14^N spin‐lattice relaxation times. A decrease of ^1^__J__(^14^N^13^C) was observed in sterically hindered secondary amines.
## Abstract One‐bond deuterium‐induced isotope shifts of ^13^C NMR (^1^Δ) for 106 sp^2^‐hybridized carbons are discussed in terms of CH bond lengths. ^1^Δ correlates linearly with the related CH bond length calculated by the MNDO MO method by the equation ^1^Δ(ppb)=8350 __r__~CH~ (Å) – 8824.
Chiral synthons containing either 13Cor 15N-labelled glycine were prepared. The 13C and 15N NMR spectra of the Ni(II) complex of the Schi † base of (S)-2-(N-benzylprolyl)aminobenzophenone and 13C-1-, 13C-2or 15N-labelled glycine were measured and assigned. The observed splitting of the carbon signal