title: Aromatic stabilization energy and magnetic properties in fulvalenes: is there a connection between these two aromaticity indices?
abstract: The nucleus-independent chemical shift (NICS) and Coulombic energy of 15 j,k-fulvalenes (j, k = 3, 5, 7, 9, 11) were investigated. It was found that in all of the hetero derivatives (j ≠ k) charge transfer between the rings occurs. It occurs when the one ring contains 4n + 1 and the other 4n + 3 π electrons, forming two rings containing numbers of π electrons closer to 4n + 2, and also when both rings contain either 4n + 3 or 4n + 1 π electrons, forming a partially aromatized ring and a partially antiaromatized ring. Both types of charge transfer are associated with aromatic stabilization energy. The NICS values are consistent with the above-described partial aromatization and antiaromatization. A semiquantitative relationship between the aromatic stabilization energy and NICS is given.
authors.affiliation: Schulich Faculty of Chemistry and The Lise Meitner-Minerva Center for Computational Quantum Chemistry, Technion - Israel Institute of Technology , Haifa 32000, Israel.
authors.forename: Amnon
authors.initials: A
authors.lastname: Stanger