Original Research ARTICLE
Aromaticity determines the relative stability of kinked vs. straight topologies in polycyclic aromatic hydrocarbons
- 1Institut de Química Teòrica i Computacional, Universitat de Barcelona, Spain
- 2Institut de Química Computacional i Catàlisi, Universitat de Girona, Spain
- 3Institut de Química Computacional i Catàlisi (IQCC), University of Girona, Spain
It is well-known that kinked phenacenes are more stable than their isomeric linear acenes, the archetypal example being phenanthrene that is more stable than anthracene by about 4–8 kcal/mol. In previous studies, the origin of the higher stability of kinked polycyclic aromatic hydrocarbons (PAHs) was found to be better π-bonding interactions, i.e., larger aromaticity, in kinked as compared to linear PAHs. Some years ago, however, Dominikowska and Palusiak (Phys. Chem. Chem. Phys. 2011, 13, 11976) found that dicationic linear anthracene is more stable than the dicationic kinked phenanthrene. Therefore, these authors showed that, in some cases, the linear topology in PAHs can be preferred over the kinked one. Our results using energy decomposition analyses in combination with the turn-upside-down approach show that the origin of the higher stability of dicationic anthracene is the same as in the neutral species, i.e. better π-bonding interactions. A similar result is found for the kinked and straight tetramethylated-pyrano-chromenes. We conclude that the aromaticity is the driven force that determines the relative stability of kinked vs. straight topologies in PAHs.
Keywords: Acenes, phenacences, energy decomposition analysis, turn upside-down approach, Density - functional theory, aromatic
Received: 19 Sep 2018;
Accepted: 30 Oct 2018.
Edited by:Nino Russo, Dipartimento di Chimica e Tecnologie Chimiche, Università della Calabria, Italy
Copyright: © 2018 Poater, Duran and Solà. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Prof. Miquel Solà, University of Girona, Institut de Química Computacional i Catàlisi (IQCC), Girona, 17071, Catalonia, Spain, email@example.com