𝔖 Bobbio Scriptorium
✦   LIBER   ✦

17O NMR investigation of p,π-interactions in α,β-unsaturated and aromatic ethers

✍ Scribed by G. A. Kalabin; D. F. Kushnarev; R. B. Valeyev; B. A. Trofimov; M. A. Fedotov

Publisher
John Wiley and Sons
Year
1982
Tongue
English
Weight
1020 KB
Volume
18
Category
Article
ISSN
0749-1581

No coin nor oath required. For personal study only.

✦ Synopsis

Abstract

The ^17^O chemical shifts have been measured for 51 α,β‐unsaturated and aromatic ethers. A good linear relationship is found between the ^17^O chemical shifts in a series of dialkyl and the corresponding alkyl vinyl ethers. Hence, the extent of p,π‐interaction, between the oxygen atom and the vinyl group in the latter series does not, apparently, depend upon branching at the α‐carbon atom in the alkyl moiety of these ethers. The PhOBu^t^ ether, however, as compared to the other alkyl phenyl ethers, shows significantly weakened p,π‐interaction, which is apparently related to the steric hindrance of this interaction. The effects of two unsaturated groups upon the ^17^O chemical shifts in the corresponding ethers are non‐additive. This is undoubtedly a result of ‘rivalry’ between these groups for conjugation with the lone electron pairs on the ethereal oxygen. The ^17^O chemical shift ranges of substituted methyl and vinyl phenyl ethers are nearly equal (≈30 ppm). An analysis of the ^17^O shielding for cyclopropyl ethers shows no observable p,σ‐conjugation in these compounds. Excellent correlation (r>0.99) between the values of ^17^O chemical shifts and the calculated (MO LCAO SCF, CNDO/2) π‐electron charges on the corresponding oxygen atoms look promising for experimental estimations of π‐electron densities on the ethereal oxygen.

📜 SIMILAR VOLUMES

Steric effects in the 17O NMR spectrosco
Steric effects in the 17O NMR spectroscopy of aromatic methyl ethers
✍ M. A. Wysocki; P. W. Jardon; G. J. Mains; E. J. Eisenbraun; D. W. Boykin 📂 Article 📅 1987 🏛 John Wiley and Sons 🌐 English ⚖ 408 KB

0 NMR spectroscopic data (natural abundance) were obtained for 19 methoxy-aromatic compounds: a series of substituted anisoles with a single ortho substituent, a series of 2,Q-disubstituted anisoles, a series of 3-substituted-1, 2-dimethoxybenzenes and three multi-substituted anisole derivatives. Th

Torsion angle relationship of the 17O NM
Torsion angle relationship of the 17O NMR chemical shift in α,β-unsaturated carbonyl compounds
✍ Francesca Mocci 📂 Article 📅 2009 🏛 John Wiley and Sons 🌐 English ⚖ 212 KB

## Abstract The torsion angle effect on the isotropic shielding of ^17^O nucleus in α,β‐unsaturated carbonyl groups is studied by means of density functional theory (DFT) calculations using a polarizable continuum model (PCM) for the solvent, employing the PBE0 functional together with the 6‐311G(d