Bucher, G. , Kohler, F. and Herges, R. (2008) Tetradehydroadamantane-1,3,5,7-di- and tetracations and their helium and hydride inclusion complexes: Spherical aromaticity and evidence for a bonding interaction between carbon and helium. Journal of Physical Chemistry A, 112(40), pp. 9906-9910. (doi: 10.1021/jp803594w)
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Abstract
The unusual stability of the experimentally known 1,3-dehydro-5,7-adamantyl dication was previously explained by four-center two-electron aromaticity with three-dimensional (tetrahedral) topology. Magnetic criteria (ACID and ring-current analysis) now demonstrate that there is also a very strong contribution from hyperconjugation with all six methylene bridges. The delocalized system of electrons thus includes all valence electrons, and the structure, therefore, should rather be described as a spherically aromatic 50-electron system. The corresponding T-d-symmetric tetracation with 48 electrons is antiaromatic and not a minimum structure. With a He atom or a hydride ion at the center of the cage, the tetracation is predicted to form a kinetically stable complex. Magnetic criteria demonstrate that the antiaromaticity is greatly reduced, and a bond analysis hints at bonding interactions between He (and H-) and the carbon atoms of the adamantane cage.
Item Type: | Articles |
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Keywords: | 2(N+1)(2) rule, acid, aromaticity, atoms, bond, cage, carbon, complex, complexes, delocalization, electron, fullerenes, ion, stability, structure, system, valence |
Status: | Published |
Refereed: | Yes |
Glasgow Author(s) Enlighten ID: | Bucher, Dr Goetz |
Authors: | Bucher, G., Kohler, F., and Herges, R. |
College/School: | College of Science and Engineering > School of Chemistry |
Journal Name: | Journal of Physical Chemistry A |
Publisher: | American Chemical Society |
ISSN: | 1089-5639 |
ISSN (Online): | 1520-5215 |
Published Online: | 11 September 2008 |
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