The components of nucleus-independent chem. shift (NICS) tensors for Dnh n-annulenes are discussed as indexes of the arom. character of electronic pi systems. The component corresponding to the principal axis perpendicular to the ring plane, NICSzz, is found to be a good measure for the characterization of the pi system of the ring. Isotropic NICS values at ring centers contain large influences from the sigma system and from all three principal components of the NICS tensor. At large distances away from the ring center, NICSzz, which is dominated by contributions from the pi system, characterizes NICS well. [on SciFinder (R)]
Titre
Induced magnetic fields in aromatic [n]-annulenes-interpretation of NICS tensor components
Publié dans
Physical Chemistry Chemical Physics
Volume
6
Numéro
2
Pages
273-276
Date
2004
ISSN
1463-9076
Note
CAN 140:320821
22-2
Physical Organic Chemistry
Department of Physical Chemistry,University of Geneva,Geneva,Switz.
Journal
written in English.
71-43-2 ([6]Annulene); 3227-76-7 ([10]Annulene); 12127-83-2 (Cyclopentadienide); 12240-33-4 (Cyclobutadienyl dication); 20829-57-6 (Cyclopropenyl anion); 26811-28-9 (Cycloheptatrienyl cation); 34510-09-3 (Cyclooctatetraene dianion); 36685-24-2 (Cyclobutadiene dianion); 37306-59-5 (Cyclooctatetraene dication) Role: PRP (Properties) (induced magnetic fields in arom. [n]-annulenes-interpretation of NICS tensor components)
Date de création de la notice
2007-10-22
