Autor según el artículo: Mulet-Gas, M., Abella, L., Dunk, P.W., Rodríguez-Fortea, A., Kroto, H.W., Poblet, J.M.

Departamento: Química Física i Inorgànica

Resumen: The formation of the smallest fullerene, C28, was recently reported using gas phase experiments combined with high-resolution FT-ICR mass spectrometry. An internally located group IV metal stabilizes the highly strained non-IPR C28 cage by charge transfer (IPR = isolated pentagon rule). Ti@C44 also appeared as a prominent peak in the mass spectra, and U@C28 was demonstrated to form by a bottom-up growth mechanism. We report here a computational analysis using standard DFT calculations and Car-Parrinello MD simulations for the family of the titled compounds, aiming to identify the optimal cage for each endohedral fullerene and to unravel key aspects of the intriguing growth mechanisms of fullerenes. We show that all the optimal isomers from C26 to C50 are linked by a simple C2 insertion, with the exception of a few carbon cages that require an additional C2 rearrangement. The ingestion of a C2 unit is always an exergonic/exothermic process that can occur through a rather simple mechanism, with the most energetically demanding step corresponding to the closure of the carbon cage. The large formation abundance observed in mass spectra for Ti@C28 and Ti@C44 can be explained by the special electronic properties of these cages and their higher relative stabilities with respect to C2 reactivity. We further verify that extrusion of C atoms from an already closed fullerene is much more energetically demanding than forming the fullerene by a bottom-up mechanism. Independent of the formation mechanism, the present investigations strongly support that, among all the possible isomers, the most stable, smaller non-IPR carbon cages are formed, a conclusion that is also valid for medium and large cages. This journal is

Acceso a la licencia de uso: https://creativecommons.org/licenses/by/3.0/es/

ISSN: 1478-6524

Página final: 686

Volumen de revista: 6

Versión del articulo depositado: info:eu-repo/semantics/publishedVersion

Enlace a la fuente original: http://pubs.rsc.org/en/Content/ArticleLanding/2015/SC/C4SC02268H#!divAbstract

DOI del artículo: 10.1039/c4sc02268h

Entidad: Universitat Rovira i Virgili.

Año de publicación de la revista: 2015

Página inicial: 675