On the Aromaticity and13 C-NMR Pattern of Pentagonal-Pyramidal Hexamethylbenzene Dication [C6 (CH3 )6 ]2+: A {C5 (CH3 )5 }− –{CCH3 }3+ Aggregate
Autor
Macleod-Carey, Desmond
Muñoz-Castro, Alvaro
Resumen
The experimentally characterized hexamethylbenzene dication C6 (CH3 )62+ 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 re-mains in the resulting pentagon ring. Here, we investigated the induced magnetic field of C6 (CH3 )6 2+ 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 C5 (CH3 )5− /CCH33+ 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.
Colecciones
Ítems relacionados
Mostrando ítems relacionados por Título, autor o materia.
-
Article
Switch from local to global aromatic character in Möbius carbon nanobelts upon dioxidation. Evaluation of magnetic behavior in neutral and charged species (2023)
Macleod-Carey, Desmond; Muñoz-Castro, Alvaro (Royal Society of Chemistry, 2023)Here we show that recent Möbius carbon nanobelts (MCNBs) can be switched from a local to a global aromatic behavior upon dioxidation. Hence, large aromatic structures can be achieved by the choice of the charge states, ... -
Article
On the 13C-NMR chemical shift anisotropy patterns and aromatic character in strained fullerenes: Computational analysis of D6h/D2d-C36 fullerene (2020)
Guajardo‐Maturana, Raul; Rodríguez-Kessler, Peter L.; MacLeod‐Carey, Desmond; Muñoz‐Castro, Álvaro (John Wiley and Sons Inc., 2020-09-05)The NMR characterization of small C36 hollow fullerene exposes a stable cage with structural features based on its strained curved π-surface in a D6h-symmetry. Our results indicate that planar-like aromatic properties of ... -
Article
Visualizing NMR-shielding effect in fullerene-ZnPc aggregates: Characteristic patterns of ZnP-based hosts and encapsulation nature from DFT calculations (2020)
MacLeod-Carey, Desmond; Rodríguez-Kessler, P. L.; Muñoz-Castro, Alvaro (John Wiley and Sons Inc, 2020-10-09)The formation of supramolecular aggregates incorporating C60 fullerenes can be followed and characterized by nuclear magnetic resonance (NMR) measurements. Here, we unravel the particular patterns provided by zinc-porphyrin ...