Bending versus Twisting Acenes – A Computational Study

Amit Manor Armon, Anjan Bedi, Veniamin Borin, Igor Schapiro*, Ori Gidron*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are widely used in organic electronic devices. The electronic, magnetic, and optical properties of PAHs can be tuned by structural modifications to the aromatic backbone to introduce an inherent distortion from planarity, such as bending or twisting. However, it remains difficult to isolate and control the effects of such distortions. Here, we sought to understand how backbone twisting and bending affect the electronic properties of acenes, as models for larger PAHs. We found that, even when highly distorted from planarity (30° per ring), acenes maintain their aromatic character and π orbital delocalization with minor mixing of the σ and π orbitals. In addition, the energy gap between the HOMO and LUMO decreases with increasing twist, while the gap is hardly affected by bending, since the energy of both orbitals increase to a similar extent. For bent acenes in the triplet state, the spin becomes more localized with increasing bend, whereas twisting produces an evenly distributed spin delocalization. These findings can guide the synthesis of PAHs with tailored properties.

Original languageAmerican English
Pages (from-to)5424-5429
Number of pages6
JournalEuropean Journal of Organic Chemistry
Volume2021
Issue number39
DOIs
StatePublished - 21 Oct 2021

Bibliographical note

Publisher Copyright:
© 2021 The Authors. European Journal of Organic Chemistry published by Wiley-VCH GmbH.

Keywords

  • Acenes
  • Aromaticity
  • Conjugation
  • Curved aromatics
  • Organic electronic materials

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