Energetic Analysis of Conjugated Hydrocarbons Using the Interacting Quantum Atoms Method

• Published in: Journal of computational chemistry 2018-07, Vol.39 (18), p.1103-1111
• Main Authors: Jara‐Cortés, Jesús, Hernández‐Trujillo, Jesús
• Format: Article
• Language: English
• Subjects: Aromatic hydrocarbons; aromatic molecules; Atomic properties; Chemical bonds; conjugated molecules; electron delocalization; electron density analysis; Hydrocarbons; hydrogen–hydrogen bonding; interacting quantum atoms; Molecular chains; nonaromatic molecules; Organic chemistry; Quantum theory
• ISSN: 0192-8651; 1096-987X
• DOI: 10.1002/jcc.25089

A number of aromatic, antiaromatic, and nonaromatic organic molecules was analyzed in terms of the contributions to the electronic energy defined in the quantum theory of atoms in molecules and the interacting quantum atoms method. Regularities were found in the exchange and electrostatic interatomic energies showing trends that are closely related to those of the delocalization indices defined in the theory. In particular, the CC interaction energies between bonded atoms allow to rationalize the energetic stabilization associated with the bond length alternation in conjugated polyenes. This approach also provides support to Clar's sextet rules devised for aromatic systems. In addition, the H⋯H bonding found in some of the aromatic molecules studied was of an attractive nature, according to the stabilizing exchange interaction between the bonded H atoms. © 2017 Wiley Periodicals, Inc. The interacting quantum atoms method allows to distinguish the energetic features of aromatic hydrocarbons from those of other organic conjugated molecules.