All-metal aromatic clusters M4 2- (M = B, Al, and Ga). Are π-electrons distortive or not?

The π-electrons in benzene, the quintessential aromatic molecule, were previously shown to be distortive, i.e., they prefer localized double bonds alternating with single bonds. It is the σ-electrons that force the double bonds to delocalize, leading to a regular, D6h geometry. Herein, we computatio...

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Detalles Bibliográficos
Autores: Poater i Teixidor, Jordi, Feixas Geronès, Ferran, Bickelhaupt, F. Matthias, Solà i Puig, Miquel
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2011
País:España
Institución:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
Repositorio:Recercat. Dipósit de la Recerca de Catalunya
OAI Identifier:oai:recercat.cat:10256/11388
Acceso en línea:http://hdl.handle.net/10256/11388
Access Level:acceso embargado
Palabra clave:Aromaticitat (Química)
Aromaticity (Chemistry)
Funcional de densitat, Teoria del
Density functionals
Descripción
Sumario:The π-electrons in benzene, the quintessential aromatic molecule, were previously shown to be distortive, i.e., they prefer localized double bonds alternating with single bonds. It is the σ-electrons that force the double bonds to delocalize, leading to a regular, D6h geometry. Herein, we computationally investigate the double-bond localizing or delocalizing propensities of σ- and π-electrons in the archetypal all-metal aromatic cluster Al4 2- and its second- and fourth-period analogs B4 2- and Ga4 2-, using Kohn-Sham molecular orbital (MO) theory at BP86/TZ2P in combination with quantitative bond energy decomposition analyses (EDA). We compare the three all-metal aromatic clusters with the structurally related organic species C4H 4 2+, C4H4, and C4H 4 2-. Our analyses reveal that the π-electrons in the group-13 M4 2- molecules have a weak preference for localizing the double bonds. Instead, the σ-electrons enforce the regular D4h equilibrium geometry with delocalized double bonds