Before and after cis-trans isomerization, the observed 13 C-NMR chemical shifts of poly(phenylacetylene) (PPA) in the solid state were investigated on the basis of 13 C-NMR chemical shift calculations within AM1 for the cis-transoidal and deflected trans-transoidal forms. Two 13 C-resonance peaks in
A 13C NMR chemical shift study of trans-fused bicyclic hexopyranoside derivatives
β Scribed by Eileen Conway; R.D. Guthrie; S.D. Gero; G. Lukacs; A.-M. Sepulchre; Edward W. Hagaman; Ernest Wenkert
- Publisher
- Elsevier Science
- Year
- 1972
- Tongue
- French
- Weight
- 180 KB
- Volume
- 13
- Category
- Article
- ISSN
- 0040-4039
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The question of the relative importance of through-bond and through-space interactions in determining 13C nmr chemical shifts, as well as the relative importance of electric field effects and induced magnetic fields are still not answered. We have examined the 13C nmr spectra of a number of sets (F,
## Abstract The analysis of the ^13^C NMR chemical shifts of 16 substituted 2βphenylthiazolidines shows that the 1,3βthiazolidβ2βyl group exerts a deshielding effect at the __ipso__ carbon (Cβ1β²) and shielding effects at the __ortho__ and __para__ positions of the benzene ring (Cβ2β² and Cβ4β²), and
## Reference Data 13C NMR Chemical Shifts of N u nsubstituted-and N-MethyI-Pyramle Derivatives 13C shielding data for 100 derivatives of pyrazole are reported. These include methyl, ethyl, n-propyl, tert-butyl, phenyl, hydroxymethyl, carboxyl, ethoxycarbonyl, cyano. amino, hydrazino, nitro, azido,
Although the subject of numerous investigations, the origins of 13C nmr chemical shifts are still not well understood.a In order to simplify the problem, we have examined a wide variety of halogen substituted (F,Cl,Br,I) compounds. The similarity of the C-X bond dipoles" should minimize contribution