Carbazolyl dicyanobenzene (CDCB) derivates exhibiting
thermally
activated delayed fluorescence (TADF) have shown themselves to be
excellent photocatalysts over recent years, particularly4CzIPN, 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-5,2-diyl))bis(3,6-di-tert-butyl-9H-carbazole),pDTCz-DPmS, for use
as a photocatalyst (PC). A comparison of the electrochemical and photophysical
properties ofpDTCz-DPmSwith4CzIPNin
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
ofpDTCz-DPmSrelative to4CzIPNpresents
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 forpDTCz-DPmS, confirming the
TADF nature, both of which are sufficiently long-lived to participate
in productive photochemistry. These combined properties makepDTCz-DPmSuseful 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
ofpDTCz-DPmScompared with4CzIPNwere
found to be advantages of this organic PC.