Unexpectedly Large Couplings Between Orthogonal Units in Anthraquinone Polymers

Rocco P. Fornari, Piotr de Silva*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

We investigate the unusual electronic properties of directly linked 1,4‐polyanthraquinones (14PAQ). The dihedral angle between the anthraquinones’ (AQ) molecular planes is found to be close to 90°. Contrary to the prevailing notion that the interaction between orthogonal units is negligible due to the broken π‐electron conjugation, the couplings between neighboring AQ units are found not to have a minimum at 90° and to be much larger than expected. The unexpectedly large electronic coupling between orthogonal AQ units is explained by the interaction between the lone pairs of the carbonylic oxygen and the π system of the neighboring unit, which allows favorable overlap between frontier molecular orbitals at the orthogonal geometry. We show that this effect, which we describe computationally for the first time, can be strengthened by adding more quinone units. The effect of thermal fluctuations on the couplings is assessed through ab initio molecular dynamics simulations. The distributions of the couplings reveal that electron transport is resilient to dynamic disorder in all systems considered, while the hole couplings are much more sensitive to disorder. We describe lone pair‐π interactions as a previously largely overlooked conjugation mechanism to be incorporated in a new class of disorder‐resilient semiconducting redox polymers.
Original languageEnglish
JournalChemistry: A European Journal
Volume25
Issue number64
Pages (from-to)14651-14658
Number of pages8
ISSN0947-6539
DOIs
Publication statusPublished - 2019

Keywords

  • Polyanthraquinone
  • Electronic couplings
  • Charge transport
  • Organic electronics
  • Polymer electrodes

Cite this

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title = "Unexpectedly Large Couplings Between Orthogonal Units in Anthraquinone Polymers",
abstract = "We investigate the unusual electronic properties of directly linked 1,4‐polyanthraquinones (14PAQ). The dihedral angle between the anthraquinones’ (AQ) molecular planes is found to be close to 90°. Contrary to the prevailing notion that the interaction between orthogonal units is negligible due to the broken π‐electron conjugation, the couplings between neighboring AQ units are found not to have a minimum at 90° and to be much larger than expected. The unexpectedly large electronic coupling between orthogonal AQ units is explained by the interaction between the lone pairs of the carbonylic oxygen and the π system of the neighboring unit, which allows favorable overlap between frontier molecular orbitals at the orthogonal geometry. We show that this effect, which we describe computationally for the first time, can be strengthened by adding more quinone units. The effect of thermal fluctuations on the couplings is assessed through ab initio molecular dynamics simulations. The distributions of the couplings reveal that electron transport is resilient to dynamic disorder in all systems considered, while the hole couplings are much more sensitive to disorder. We describe lone pair‐π interactions as a previously largely overlooked conjugation mechanism to be incorporated in a new class of disorder‐resilient semiconducting redox polymers.",
keywords = "Polyanthraquinone, Electronic couplings, Charge transport, Organic electronics, Polymer electrodes",
author = "Fornari, {Rocco P.} and {de Silva}, Piotr",
year = "2019",
doi = "10.1002/chem.201903227",
language = "English",
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pages = "14651--14658",
journal = "Chemistry: A European Journal",
issn = "0947-6539",
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Unexpectedly Large Couplings Between Orthogonal Units in Anthraquinone Polymers. / Fornari, Rocco P.; de Silva, Piotr.

In: Chemistry: A European Journal, Vol. 25, No. 64, 2019, p. 14651-14658.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Unexpectedly Large Couplings Between Orthogonal Units in Anthraquinone Polymers

AU - Fornari, Rocco P.

AU - de Silva, Piotr

PY - 2019

Y1 - 2019

N2 - We investigate the unusual electronic properties of directly linked 1,4‐polyanthraquinones (14PAQ). The dihedral angle between the anthraquinones’ (AQ) molecular planes is found to be close to 90°. Contrary to the prevailing notion that the interaction between orthogonal units is negligible due to the broken π‐electron conjugation, the couplings between neighboring AQ units are found not to have a minimum at 90° and to be much larger than expected. The unexpectedly large electronic coupling between orthogonal AQ units is explained by the interaction between the lone pairs of the carbonylic oxygen and the π system of the neighboring unit, which allows favorable overlap between frontier molecular orbitals at the orthogonal geometry. We show that this effect, which we describe computationally for the first time, can be strengthened by adding more quinone units. The effect of thermal fluctuations on the couplings is assessed through ab initio molecular dynamics simulations. The distributions of the couplings reveal that electron transport is resilient to dynamic disorder in all systems considered, while the hole couplings are much more sensitive to disorder. We describe lone pair‐π interactions as a previously largely overlooked conjugation mechanism to be incorporated in a new class of disorder‐resilient semiconducting redox polymers.

AB - We investigate the unusual electronic properties of directly linked 1,4‐polyanthraquinones (14PAQ). The dihedral angle between the anthraquinones’ (AQ) molecular planes is found to be close to 90°. Contrary to the prevailing notion that the interaction between orthogonal units is negligible due to the broken π‐electron conjugation, the couplings between neighboring AQ units are found not to have a minimum at 90° and to be much larger than expected. The unexpectedly large electronic coupling between orthogonal AQ units is explained by the interaction between the lone pairs of the carbonylic oxygen and the π system of the neighboring unit, which allows favorable overlap between frontier molecular orbitals at the orthogonal geometry. We show that this effect, which we describe computationally for the first time, can be strengthened by adding more quinone units. The effect of thermal fluctuations on the couplings is assessed through ab initio molecular dynamics simulations. The distributions of the couplings reveal that electron transport is resilient to dynamic disorder in all systems considered, while the hole couplings are much more sensitive to disorder. We describe lone pair‐π interactions as a previously largely overlooked conjugation mechanism to be incorporated in a new class of disorder‐resilient semiconducting redox polymers.

KW - Polyanthraquinone

KW - Electronic couplings

KW - Charge transport

KW - Organic electronics

KW - Polymer electrodes

U2 - 10.1002/chem.201903227

DO - 10.1002/chem.201903227

M3 - Journal article

VL - 25

SP - 14651

EP - 14658

JO - Chemistry: A European Journal

JF - Chemistry: A European Journal

SN - 0947-6539

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ER -