Etude conformationnelle des alcényl phénylcétones par spectrographies infrarouge, ultraviolette et par l'utilisation de l'effet Overhauser nucléaire et de complexe de lanthanide Eu(dpm)3 en résonance magnétique nucléaire
| Autor: | Trinh Minh-Chau, Nguyen Thoai |
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| Rok vydání: | 1974 |
| Předmět: | |
| Zdroj: | Canadian Journal of Chemistry. 52:1331-1338 |
| ISSN: | 1480-3291 0008-4042 |
| DOI: | 10.1139/v74-203 |
| Popis: | By the use of i.r., u.v. and n.m.r. (n.O.e. and europium chelates) we have shown that a series of phenyl ketones (R1R2C=CR3—CO—C6H5) exist within the s-cis conformation probably because of the steric bulk of the benzene ring. When these ketones have an alkyl substituent (R3=Me, Et) on the carbon atom α to the carbonyl group, the molecule is no longer planar. The molecular torsion in this case is not around the CO—C6H5, bond but rather at the CO—C= bond. The resulting dihedral angle is about 65°. We propose a tabular method which together with the use of Eu(dpm)3 allows rapid determination of the preferred conformation of non rigid α,β-unsaturated ketones and in the case of non-planar conformations allows the estimation of the dihedral angle between the C=C and C=O chromophores. [Journal translation] |
| Databáze: | OpenAIRE |
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