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17 O NMR Spectra of Carbonyl Compounds ArCOX: Influence of Groups X on the Polarity of the Carbonyl Group
Author(s) -
Dahn Hans,
Péchy Peter,
Van Toan Vien
Publication year - 1997
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/(sici)1097-458x(199709)35:9<589::aid-omr134>3.0.co;2-l
Subject(s) - chemistry , electrophile , aryl , polarity (international relations) , carbonyl group , resonance (particle physics) , spectral line , group (periodic table) , inductive effect , medicinal chemistry , stereochemistry , crystallography , organic chemistry , catalysis , biochemistry , alkyl , physics , astronomy , cell , particle physics
The 17 O shift values of para ‐substituted benzoyl compounds p ‐YC 6 H 4 COX (X=H, CF 3 , COOEt, Br, Cl, F, SEt, OCOAr, OH, O ‐ Na + , NH 2 ) were measured. The 17 O shielding values δ( 17 O) of these and other aryl‐unsubstituted benzoyl compounds (Y=H) follow the electron‐donating power of X (resonance), whereas inductive electron attractors (CF 3 , COOEt) show only small effects. The sensitivity of the shift values to donor/attractor para substituents Y, measured as the Hammett–Taft ρ + =δ( 17 O)/σ + , follows both the resonance and the inductive effects; combined with the δ( 17 O) values, it is proposed as an empirical measure of the polarity (electrophilicity) of the carbonyl group (35 types of COX in Table 1).