Donor Influence on the Optoelectronic Properties of N‐Substituted Tetraphenylimidazole Derivatives

Matulaitis, Tomas; dos Santos, Paloma L.; Tsuchiya, Youichi; Cordes, David B.; Slawin, Alexandra M.Z.; Adachi, Chihaya; Samuel, Ifor D.W.; Zysman‐Colman, Eli

Abstract

Three new 1,2,4,5-tetraphenylimidazole derivatives, 9,9-dimethyl-10-(4-(2,4,5-triphenyl-1H-imidazol-1-yl)phenyl)-9,10-dihydroacridine (DMAC-TPI), 10-(4-(2,4,5-triphenyl-1H-imidazol-1-yl)phenyl)-10H-phenoxazine (PXZ-TPI), and 10-(4-(2,4,5-triphenyl-1H-imidazol-1-yl)phenyl)-10H-phenothiazine (PTZ-TPI), bearing different electron donors at the N1 position of the imidazole were synthesised and characterised. DMAC-TPI and PXZ-TPI showed narrow emission at λPL of 388 and 418 nm in toluene, and in doped films in Zeonex polymer (1 wt.%) at λPL 381 and 407 nm, respectively, with a full width at half maximum (FWHM) ranging 0.42-0.44 eV. DMAC-TPI and PXZ-TPI are predicted to show very low oscillator strength for the low-energy transitions, which aligns to the observed low photoluminescence quantum yields. Both molecules showed a singlet-triplet energy gap (ΔEST of around 1.2 eV) that is much too large to enable reverse intersystem crossing and thermally activated delayed fluorescence. Connecting a donor group to TPI at the N1 position can lead to room temperature phosphorescence (RTP), as the example of PTZ-TPI showed.

Citation

Matulaitis, T., dos Santos, P. L., Tsuchiya, Y., Cordes, D. B., Slawin, A. M., Adachi, C., Samuel, I. D., & Zysman‐Colman, E. (2023). Donor Influence on the Optoelectronic Properties of N‐Substituted Tetraphenylimidazole Derivatives. ChemistrySelect, 8(9), https://doi.org/10.1002/slct.202300274

• Journal Article Type: Article
• Acceptance Date: Feb 9, 2023
• Online Publication Date: Feb 28, 2023
• Publication Date: 2023
• Deposit Date: Jun 19, 2023
• Publicly Available Date: Jun 19, 2023
• Journal: ChemistrySelect
• Electronic ISSN: 2365-6549
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 8
• Issue: 9
• DOI: https://doi.org/10.1002/slct.202300274
• Public URL: https://durham-repository.worktribe.com/output/1170690