%0 Journal Article
%T Diagnosis of the 考-, 羽- and (考+羽)-Aromaticity by the Shape of the NICSzz-Scan Curves and Symmetry-Based Selection Rules
%A Athanassios C. Tsipis
%A Ioannis G. Depastas
%A Constantinos A. Tsipis
%J Symmetry
%D 2010
%I MDPI AG
%R 10.3390/sym2010284
%X The NICSzz-scan curves of aromatic organic, inorganic and ※all-metal§ molecules in conjunction with symmetry-based selection rules provide efficient diagnostic tools of the 考-, 羽- and/or double (考 + 羽)-aromaticity. The NICSzz-scan curves of 考-aromatic molecules are symmetric around the z-axis, having half-band widths approximately less than 3 ˋ with the induced diatropic ring current arising from Tx,y-allowed transitions involving exclusively 考-type molecular orbitals. Broad NICSzz-scan curves (half-band width approximately higher than 3 ˋ) characterize double (考 + 羽)-aromaticity, the chief contribution to the induced diatropic ring current arising from Tx,y-allowed transitions involving both 考- and 羽-type molecular orbitals. NICSzz-scan curves exhibiting two maxima at a certain distance above and below the molecular plane are typical for (考 + 羽)-aromatics where the 羽-diatropic ring current overwhelms the 考-type one. In the absence of any contribution from the 考-diatropic ring current, the NICSzz(0) value is close to zero and the molecule exhibits pure 羽-aromaticity.
%K aromaticity
%K delocalization
%K 考-
%K 羽-
%K (考+羽)-aromaticity
%K NICSzz-scan
%K density functional theory (DFT)
%U http://www.mdpi.com/2073-8994/2/1/284