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Saturated amine oxides: Part 4 . Steric and electric field effects on the 17 O NMR chemical shifts of saturated six‐membered azaheterocyclic amine oxides
Author(s) -
Potmischil Francisc,
Magiera Damian,
Duddeck Helmut,
Buddrus Joachim
Publication year - 2001
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.888
Subject(s) - steric effects , chemistry , chemical shift , amine gas treating , computational chemistry , amine oxide , organic chemistry , alkyl
The 17 O NMR chemical shifts of 14 N ‐methylpiperidine‐ N ‐oxides and five N ‐methyltetradecahydroacridine‐ N ‐oxides were measured. The effects of steric factors, such as γ‐ gauche and 1,3‐ syn ‐axial interactions of the N + —O − oxygen, on the 17 O chemical shifts are discussed, and evidence for the main contribution of electrostatic interactions, rather than true steric compression, to the so‐called ‘steric effects’ on 17 O chemical shifts of alcohols, ethers, sulfoxides and amine oxides is presented. For conformationally mobile compounds, the discussion of the chemical shifts is assisted by results from molecular mechanics (MM+) calculations. Copyright © 2001 John Wiley & Sons, Ltd.