Downfield Proton Chemical Shifts Are Not Reliable Aromaticity Indicators
2005
Résumé
The downfield chem. shifts of arene hydrogens (delta 1H) are due only in part to the pi ring current contribution [sigma.dblvert.(pi)]; local framework effects are equally important. Neither proton chem. shifts nor even sigma.dblvert.(pi) tensor elements, per se, are reliable aromaticity indicators. Unsatd. polycyclic hydrocarbons with nonarom. quinoid structures have delta 1H and sigma.dblvert.(pi) values in the "arom. range". Conversely, numerous arom. protons, including those in five-membered ring heterocycles, resonate in the "nonarom. range". [on SciFinder (R)]
Détails
Titre
Downfield Proton Chemical Shifts Are Not Reliable Aromaticity Indicators
Auteur(s)
Wannere, Chaitanya S. ; Corminboeuf, Clemence ; Allen, Wesley D. ; Schaefer, Henry F. III ; Schleyer, Paul von Rague
Publié dans
Organic Letters
Volume
7
Numéro
8
Pages
1457-1460
Date
2005
Mots-clés (libres)
Density functional theory (PW91; downfield NMR proton chem. shifts are not reliable aromaticity indicators); NMR (chem. shift; downfield NMR proton chem. shifts are not reliable aromaticity indicators); IGLO; Ring current (downfield NMR proton chem. shifts are not reliable aromaticity indicators); Polycyclic compounds Role: PRP (Properties) (hydrocarbons; unsatd.; downfield NMR proton chem. shifts are not reliable aromaticity indicators); Aromaticity (index; downfield NMR proton chem. shifts are not reliable aromaticity indicators); Hydrocarbons Role: PRP (Properties) (polycyclic; unsatd.; downfield NMR proton chem. shifts are not reliable aromaticity indicators); aromaticity indicator downfield nmr proton chem
Note
CAN 142:429747 22-2 Physical Organic Chemistry Center for Computational Chemistry, Department of Chemistry,University of Georgia,Athens,GA,USA. Journal 1523-7060 written in English. 85-01-8 (Phenanthrene); 91-20-3 (Naphthalene); 92-24-0 (Naphthacene); 95-13-6 (1H-Indene); 120-12-7 (Anthracene); 253-01-0 (Cyclobuta[1,2:3,4]dicyclopentene); 257-24-9 (Heptalene); 268-37-1 (2H-Benz[f]indene); 270-53-1 (2H-Indene); 275-51-4 (Azulene); 4026-23-7 (Bicyclo[4.2.0]octa-1,3,5,7-tetraene); 850661-43-7; 850661-44-8 Role: PRP (Properties) (downfield NMR proton chem. shifts are not reliable aromaticity indicators)
Laboratoires
LCMD
Le document apparaît dans
Production scientifique et compétences > SB - Faculté des sciences de base > ISIC - Institut des sciences et ingénierie chimiques > LCMD - Laboratoire de design moléculaire computationnel
Publications validées par des pairs
Travail hors EPFL
Articles de journaux
Publié
Publications validées par des pairs
Travail hors EPFL
Articles de journaux
Publié
Date de création de la notice
2007-10-22