Moving beyond cyanoarene thermally activated delayed fluorescence compounds as photocatalysts : an assessment of the performance of a pyrimidyl sulfone photocatalyst in comparison to 4CzIPN
Abstract
Carbazolyl dicyanobenzene (CDCB) derivates exhibiting thermally activated delayed fluorescence (TADF) have shown themselves to be excellent photocatalysts over recent years, particularly 4CzIPN, although investigation into organic TADF compounds as photocatalysts outside of the CDCB group has been limited. Herein, we report an alternative donor-acceptor TADF structure, 9,9′-(sulfonylbis(pyrimidine-5,2diyl))bis(3,6-di-tert-butyl-9H-carbazole), pDTCz-DPmS, for use as a photocatalyst (PC). A comparison of the electrochemical and photophysical properties of pDTCzDPmS with 4CzIPN in a range of solvents identifies the former as a better ground state reducing agent and photoreductant, while both exhibit similar oxidation capabilities in the ground and excited state. The increased conjugation of pDTCz-DPmS relative to 4CzIPN presents a more intense CT band in the UV-Vis absorption spectrum, aiding in the light absorption of this molecule. Prompt and delayed emission lifetimes are observed for pDTCz-DPmS, confirming the TADF nature, both of which are significantly long lived to participate in productive photochemistry. These combined properties make pDTCz-DPmS useful in photocatalysis reactions, covering a range of photoredox oxidative and reductive quenching reactions, as well as those involving a dual Ni(II) cocatalyst, alongside energy transfer processes. The higher triplet energy and increased photostability of pDTCz-DPmS compared with 4CzIPN were found to be advantages of this organic photocatalyst.
Citation
Bryden , M A , Millward , F D , Matulaitis , T , Chen , D , Villa , M , Fermi , A , Cetin , S , Ceroni , P & Zysman-Colman , E 2022 , ' Moving beyond cyanoarene thermally activated delayed fluorescence compounds as photocatalysts : an assessment of the performance of a pyrimidyl sulfone photocatalyst in comparison to 4CzIPN ' , The Journal of Organic Chemistry , vol. Articles ASAP . https://doi.org/10.1021/acs.joc.2c01137
Publication
The Journal of Organic Chemistry
Status
Peer reviewed
ISSN
0022-3263Type
Journal article
Rights
Copyright © 2022 The Authors. Published by American Chemical Society. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Description
Funding: We are grateful to the University of St Andrews, Syngenta, the EPSRC Centre for Doctoral Training in Critical Resource Catalysis (CRITICAT) for financial support [Ph.D. studentship to “M.B.”; Grant code: EP/L016419/1].EZ-C is a Royal Society Leverhulme Trust Senior Research fellow (SRF\R1\201089). E.Z.-C., S.C. and P.C. acknowledge the European Union H2020 research and innovation program under the Marie Skłodowska Curie Grant Agreement (PhotoReAct, No 956324).Collections
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