On the Aromaticity and <sup>13</sup>C-NMR Pattern of Pentagonal-Pyramidal Hexamethylbenzene Dication [C<sub>6</sub>(CH<sub>3</sub>)<sub>6</sub>]<sup>2+</sup>: A {C<sub>5</sub>(CH<sub>3</sub>)<sub>5</sub>}<sup>−</sup>–{CCH<sub>3</sub>}<sup>3+</sup> Aggregate
The experimentally characterized hexamethylbenzene dication C<sub>6</sub>(CH<sub>3</sub>)<sub>6</sub><sup>2+</sup> shows a pentagonal-pyramidal structure involving a carbon-capped five-membered ring. The structural characterization of this hypercoordin...
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MDPI AG
2021-11-01
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| Online Access: | https://www.mdpi.com/2624-8549/3/4/97 |
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| author | Desmond MacLeod-Carey Alvaro Muñoz-Castro |
| author_facet | Desmond MacLeod-Carey Alvaro Muñoz-Castro |
| author_sort | Desmond MacLeod-Carey |
| collection | DOAJ |
| description | The experimentally characterized hexamethylbenzene dication C<sub>6</sub>(CH<sub>3</sub>)<sub>6</sub><sup>2+</sup> shows a pentagonal-pyramidal structure involving a carbon-capped five-membered ring. The structural characterization of this hypercoordination (or hypervalency) gives rise if the aromatic behavior remains in the resulting pentagon ring. Here, we investigated the induced magnetic field of C<sub>6</sub>(CH<sub>3</sub>)<sub>6</sub><sup>2+</sup> to gain a deeper understanding of the resulting non-classical structural situation in a representative pentagonal-pyramidal structure. Our results support the view of a C<sub>5</sub>(CH<sub>3</sub>)<sub>5</sub><sup>−</sup>/CCH<sub>3</sub><sup>3+</sup> structure, depicting a π-aromatic pentamethylcyclopentadienyl anion with a 6π-electron kernel, with a capped carbon which does not decrease the characteristic shielding cone property of the aromatic ring. Hence, carbon-capped rings are suggested to retain the aromatic behavior from the former aromatic ring. We expect that the analysis of both the overall magnetic response and NMR chemical shifts may be informative to unravel the characteristic patterns in the formation of hypervalent carbon atoms involving non-classical chemical environments. |
| first_indexed | 2024-03-10T04:24:39Z |
| format | Article |
| id | doaj.art-417ecb5e30cd434e9fcaeea353b9cb30 |
| institution | Directory Open Access Journal |
| issn | 2624-8549 |
| language | English |
| last_indexed | 2024-03-10T04:24:39Z |
| publishDate | 2021-11-01 |
| publisher | MDPI AG |
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| spelling | doaj.art-417ecb5e30cd434e9fcaeea353b9cb302023-11-23T07:41:05ZengMDPI AGChemistry2624-85492021-11-01341363137010.3390/chemistry3040097On the Aromaticity and <sup>13</sup>C-NMR Pattern of Pentagonal-Pyramidal Hexamethylbenzene Dication [C<sub>6</sub>(CH<sub>3</sub>)<sub>6</sub>]<sup>2+</sup>: A {C<sub>5</sub>(CH<sub>3</sub>)<sub>5</sub>}<sup>−</sup>–{CCH<sub>3</sub>}<sup>3+</sup> AggregateDesmond MacLeod-Carey0Alvaro Muñoz-Castro1Laboratorio de Química Inorgánica y Materiales Moleculares, Universidad Autónoma de Chile, Llano Subercaceaux 2801, San Miguel, Santiago 8900000, ChileLaboratorio de Química Inorgánica y Materiales Moleculares, Universidad Autónoma de Chile, Llano Subercaceaux 2801, San Miguel, Santiago 8900000, ChileThe experimentally characterized hexamethylbenzene dication C<sub>6</sub>(CH<sub>3</sub>)<sub>6</sub><sup>2+</sup> shows a pentagonal-pyramidal structure involving a carbon-capped five-membered ring. The structural characterization of this hypercoordination (or hypervalency) gives rise if the aromatic behavior remains in the resulting pentagon ring. Here, we investigated the induced magnetic field of C<sub>6</sub>(CH<sub>3</sub>)<sub>6</sub><sup>2+</sup> to gain a deeper understanding of the resulting non-classical structural situation in a representative pentagonal-pyramidal structure. Our results support the view of a C<sub>5</sub>(CH<sub>3</sub>)<sub>5</sub><sup>−</sup>/CCH<sub>3</sub><sup>3+</sup> structure, depicting a π-aromatic pentamethylcyclopentadienyl anion with a 6π-electron kernel, with a capped carbon which does not decrease the characteristic shielding cone property of the aromatic ring. Hence, carbon-capped rings are suggested to retain the aromatic behavior from the former aromatic ring. We expect that the analysis of both the overall magnetic response and NMR chemical shifts may be informative to unravel the characteristic patterns in the formation of hypervalent carbon atoms involving non-classical chemical environments.https://www.mdpi.com/2624-8549/3/4/97carbonhypercoordinationaromaticityshieldingDFT |
| spellingShingle | Desmond MacLeod-Carey Alvaro Muñoz-Castro On the Aromaticity and <sup>13</sup>C-NMR Pattern of Pentagonal-Pyramidal Hexamethylbenzene Dication [C<sub>6</sub>(CH<sub>3</sub>)<sub>6</sub>]<sup>2+</sup>: A {C<sub>5</sub>(CH<sub>3</sub>)<sub>5</sub>}<sup>−</sup>–{CCH<sub>3</sub>}<sup>3+</sup> Aggregate Chemistry carbon hypercoordination aromaticity shielding DFT |
| title | On the Aromaticity and <sup>13</sup>C-NMR Pattern of Pentagonal-Pyramidal Hexamethylbenzene Dication [C<sub>6</sub>(CH<sub>3</sub>)<sub>6</sub>]<sup>2+</sup>: A {C<sub>5</sub>(CH<sub>3</sub>)<sub>5</sub>}<sup>−</sup>–{CCH<sub>3</sub>}<sup>3+</sup> Aggregate |
| title_full | On the Aromaticity and <sup>13</sup>C-NMR Pattern of Pentagonal-Pyramidal Hexamethylbenzene Dication [C<sub>6</sub>(CH<sub>3</sub>)<sub>6</sub>]<sup>2+</sup>: A {C<sub>5</sub>(CH<sub>3</sub>)<sub>5</sub>}<sup>−</sup>–{CCH<sub>3</sub>}<sup>3+</sup> Aggregate |
| title_fullStr | On the Aromaticity and <sup>13</sup>C-NMR Pattern of Pentagonal-Pyramidal Hexamethylbenzene Dication [C<sub>6</sub>(CH<sub>3</sub>)<sub>6</sub>]<sup>2+</sup>: A {C<sub>5</sub>(CH<sub>3</sub>)<sub>5</sub>}<sup>−</sup>–{CCH<sub>3</sub>}<sup>3+</sup> Aggregate |
| title_full_unstemmed | On the Aromaticity and <sup>13</sup>C-NMR Pattern of Pentagonal-Pyramidal Hexamethylbenzene Dication [C<sub>6</sub>(CH<sub>3</sub>)<sub>6</sub>]<sup>2+</sup>: A {C<sub>5</sub>(CH<sub>3</sub>)<sub>5</sub>}<sup>−</sup>–{CCH<sub>3</sub>}<sup>3+</sup> Aggregate |
| title_short | On the Aromaticity and <sup>13</sup>C-NMR Pattern of Pentagonal-Pyramidal Hexamethylbenzene Dication [C<sub>6</sub>(CH<sub>3</sub>)<sub>6</sub>]<sup>2+</sup>: A {C<sub>5</sub>(CH<sub>3</sub>)<sub>5</sub>}<sup>−</sup>–{CCH<sub>3</sub>}<sup>3+</sup> Aggregate |
| title_sort | on the aromaticity and sup 13 sup c nmr pattern of pentagonal pyramidal hexamethylbenzene dication c sub 6 sub ch sub 3 sub sub 6 sub sup 2 sup a c sub 5 sub ch sub 3 sub sub 5 sub sup sup cch sub 3 sub sup 3 sup aggregate |
| topic | carbon hypercoordination aromaticity shielding DFT |
| url | https://www.mdpi.com/2624-8549/3/4/97 |
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