Aromaticity, the Huckel 4n+2 Rule and Magnetic Current

Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216224%3A14740%2F17%3A00098564" target="_blank" >RIV/00216224:14740/17:00098564 - isvavai.cz</a>
Result on the web
<a href="http://onlinelibrary.wiley.com/doi/10.1002/slct.201602080/full" target="_blank" >http://onlinelibrary.wiley.com/doi/10.1002/slct.201602080/full</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1002/slct.201602080" target="_blank" >10.1002/slct.201602080</a>

Result language
angličtina
Original language name
Aromaticity, the Huckel 4n+2 Rule and Magnetic Current
Original language description
Quantum chemical calculations using density functional theory and correlated ab initio methods of the 10 pi-electron systems (N6H6)(2+) and C2N4H6 show that the planar forms are no minima on the potential energy surfaces. The twisted ring structures of the two species are energy minima, but acyclic isomers are much lower in energy. The planar geometries sustain strong diamagnetic ring current comparable with that of benzene. In contrast, the calculated multicenter normalized Giambiagi electron delocalization index ING suggests that pi- delocalization in planar (N6H6)(2+) and C2N4H6 is much weaker than in benzene. Since aromaticity is synonymous for a particular stability of cyclic delocalized systems, it may be stated that calculation or measurement of magnetic chemical shifts due to induced ring currents is not a reliable method to ascertain the aromatic character of a molecule. Aromatic compounds exhibit ring current induced magnetic shielding, but the reverse conclusion that ring current induced magnetic shielding identifies aromaticity is not justified. Furthermore, the 4n+ 2 rule as indicator of aromatic stabilization should only be used in conjunction with the ring size; the nature of the occupied pi orbitals must always be examined.
Czech name
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Czech description
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Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
—
OECD FORD branch
10403 - Physical chemistry

Project
<a href="/en/project/LM2015085" target="_blank" >LM2015085: CERIT Scientific Cloud</a><br>
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year
2017
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

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