Issue 12, 2022

An S-shaped double helicene showing both multi-resonance thermally activated delayed fluorescence and circularly polarized luminescence

Abstract

We present the first example of a multi-resonant thermally activated delayed fluorescent (MR-TADF) extended helicene, Hel-DiDiKTa. This S-shaped double helicene exhibits sky-blue emission, a singlet–triplet energy gap, ΔEST, of 0.15 eV and narrow emission at a peak maximum of 473 nm with a full-width at half-maximum of 44 nm in toluene. The MR-TADF character is confirmed by the small degree of positive solvatochromism and temperature-dependent increase in intensity of the delayed emission. The chiroptical properties of the separated enantiomers are similar to other large helicenes with comparable dissymmetry values, but with the added benefit of MR-TADF. (P)-Hel-DiDiKTa is stable towards enantiomerization, with a Gibbs free energy of activation for enantiomerization (ΔGe) of 31 ± 2 kcal mol−1 at 298 K, a value similar to other reported double helicenes. (P)-Hel-DiDiKTa is also thermally stable, with a 5% weight loss at 399 °C revealed by thermogravimetric analysis (TGA). Thus, this study further strengthens the burgeoning area of chiral TADF emitters for use in cutting-edge optoelectronic and photocatalytic molecules and materials.

Graphical abstract: An S-shaped double helicene showing both multi-resonance thermally activated delayed fluorescence and circularly polarized luminescence

Supplementary files

Article information

Article type
Paper
Submitted
14 Janv. 2022
Accepted
24 Janv. 2022
First published
27 Janv. 2022
This article is Open Access
Creative Commons BY license

J. Mater. Chem. C, 2022,10, 4861-4870

An S-shaped double helicene showing both multi-resonance thermally activated delayed fluorescence and circularly polarized luminescence

J. M. dos Santos, D. Sun, J. M. Moreno-Naranjo, D. Hall, F. Zinna, S. T. J. Ryan, W. Shi, T. Matulaitis, D. B. Cordes, A. M. Z. Slawin, D. Beljonne, S. L. Warriner, Y. Olivier, M. J. Fuchter and E. Zysman-Colman, J. Mater. Chem. C, 2022, 10, 4861 DOI: 10.1039/D2TC00198E

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