Proper Resonance Depiction of Acylium Cation: A High-Level and Student Computational Investigation

• Autores: Brian J. Esselman, Nicholas J. Hill
• Localización: Journal of chemical education, ISSN 0021-9584, Vol. 92, Nº 4, 2015, págs. 660-663
• Idioma: inglés
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• Resumen

  • The electronic and molecular structure of the acylium cation ([CH3CO]+, 1) receives varied treatment in undergraduate textbooks and online resources. The overall structure of 1 is typically represented as an equal combination of resonance structures containing C–O triple and double bonds, the latter structure occasionally being shown with a bent C–C–O bond angle. This description is inconsistent with available experimental and theoretical data, all of which indicate that 1 is a linear molecule containing a C≡O bond, and can lead students to a false conception of structure, conjugation, and charge distribution. A set of simple computational exercises is reported that allows students to calculate and rationalize the most accurate resonance representation of 1.