Continued interest in the origin of the magnetic non-equivalence of protons in methylene groups attached to asymmetric centres (1) prompts us tc report our results with some 1,2disubstituted ferrocenes. Several factors, including molecular asymmetry (2)) 2-substituent asymmetry (3), unequal conform
Non-equivalence of the methylene protons in octaethylporphinatothallium(III)
β Scribed by R.J. Abraham; K.M. Smith
- Publisher
- Elsevier Science
- Year
- 1971
- Tongue
- French
- Weight
- 197 KB
- Volume
- 12
- Category
- Article
- ISSN
- 0040-4039
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π SIMILAR VOLUMES
The magnetic equivalence or non-equivalence of the methylene hydrogens of a benzyl group has proven to be an effective probe for chirality in a substrate.' An AB quartet for the nmr resonance signal of the aliphatic protons of a single benzyl substituent is positive evidence for chirality( in the sy
PCls is added portionwise with vigorous stirring to liquid NH3 at -70 'C. An almost clear solution is obtained which yields a white powder when the NH3 is evaporated off. The weight of the final precipitate reveals that 8 moles of NH3 have been taken up for each mole of PCI5. The product is kept at
## Abstract The chemical shift nonβequivalence of the methylene protons adjacent to the quaternary nitrogen in compounds of the type has been investigated. The behaviour of the examined compounds is interpreted in terms of different rotation rates around the three Cο£ΏN^β^ bonds. The vicinal and gem
The methylene protons of dibenzyl sulphoxide are magnetically equivalent in low dielectric and non-equivalent in high dielectric constant solvents, while for diphenacyl sulphoxide this behaviour is reversed. In both cases, the variation in the magnitude of the non-equivalence reflects a greater down