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 language | English |
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Journal | Chemistry - A European Journal |
Volume | 25 |
Issue number | 64 |
Pages (from-to) | 14651-14658 |
Number of pages | 8 |
ISSN | 0947-6539 |
DOIs | |
Publication status | Published - 2019 |
Keywords
- Polyanthraquinone
- Electronic couplings
- Charge transport
- Organic electronics
- Polymer electrodes