Unexpectedly Large Couplings Between Orthogonal Units in Anthraquinone Polymers

Abstract

The unusuale lectronic properties of directly linked 1,4-polyanthraquinones( 14PAQs) are investigated. The dihedral angle between the molecular planes of anthraquinones (AQs) is found to be close to 908.C ontraryt ot he prevailing notion that the interaction between orthogonal units is negligible due to broken p-electron conjugation,t he coupling between neighboring AQ units does not have am inimum at 908 and is much largert han that expected. The unexpectedly large electronic coupling betweeno rthogonalA Qu nits is explained by the interaction between the lone pairs of the carbonyl oxygen and the p system of the neighboringu nit, which allows favorableo verlap betweenf rontierm olecular orbitalsa tt he orthogonal geometry. It is shown that this effect, which is described computationally for the first time, can be strengthened by adding more quinone units. The effecto ft hermal fluctuationso nt he couplings is assessed through ab initio molecular dynamicss imulations. The distributions of the couplings revealt hat electron transporti sr esilientt od ynamic disorder in all systemsc onsidered,w hereas the hole couplings are much more sensitive to disorder. Lone pair-p interactions are described, as ap reviously largely overlooked conjugation mechanism,f or incorporation into an ew class of disorder-resilient semiconducting redox polymers.[a] Dr.pdes@dtu.dk [**] Ap revious versiono ft his manuscript has been deposited on ap reprint server (https://doi.org/10.26434/chemrxiv.8275238.v1).Supporting information and the ORCID identification number(s) for the author(s) of this articlecan be found under: https://doi.

Molecular modeling of organic redox‐active battery materials

“…Araujo et al calculated the electrochemical properties of polypyridine and polythiophene and the infinite chain limit by extrapolating the result of oligomers of varying length 110 . In our work, we studied dimers of directly linked 1,4‐polyanthraquinone (14PAQ) which is an OEM with very good electrochemical properties 111 . Despite nearly orthogonal arrangement of neighboring monomers, 14PAQ shows reasonably high conductivity, on par with organic semiconductors specifically designed for this purpose.…”

“…The latter method was found to be more reliable. Reprinted with permission from Reference 111. Copyright 2019 John Wiley and Sons…”