Syntheses of Diverse Donor-Substituted Bisbenzofuro[2,3-b:3’,2’- e]pyridines (BBZFPys) via Pd Catalysis, and Their Photophysical Properties

Itai, Yuhei; Nishii, Yuji; Stachelek, Patrycja; Data, Przemyslaw; Takeda, Youhei; Minakata, Satoshi; Miura, Masahiro

Abstract

A series of bisbenzofuro[2,3-b:3’,2’-e]pyridines (BBZFPys) bearing a chlorine functionality have been efficiently synthesized through a Pd-catalyzed double oxidative intramolecular C–H/C–H coupling of mono-chlorinated 2,6-diaryloxypyridines. The subsequent Buchwald-Hartwig amination of the chlorinated BBZFPys allowed for the access to a new class of donor-acceptor (D-A) π-conjugated compounds that comprise of BBZFPy as an electron-acceptor (A) and diarylamines as a donor (D) units. The investigation of the steady-state photophysical properties of the prepared D-A compounds revealed that they are emissive in both of solution and solid states in blue-to-green color region. The singlet-triplet energy splitting (DEST) was found much smaller than that of substituent- free BBZFPy (0.70 eV), ranging from 0.01 to 0.56 eV. The time-resolved spectroscopy revealed that the D-A compounds comprising of a bis(tert-butyl)carbazole as the D and CF3-attached BBZFPy as the A showed delayed fluorescence (DF) in a non-polar matrix host material (Zeonex®), while in a polar matrix (DPEPO), room-temperature phosphorescence (RTP) was faintly observed. Furthermore, organic light-emitting diodes (OLEDs) fabricated with the D-A compounds as a blue-emitter showed a moderate external quantum efficiencies (EQEs) up to 1.5%.

Citation

Itai, Y., Nishii, Y., Stachelek, P., Data, P., Takeda, Y., Minakata, S., & Miura, M. (2018). Syntheses of Diverse Donor-Substituted Bisbenzofuro[2,3-b:3’,2’- e]pyridines (BBZFPys) via Pd Catalysis, and Their Photophysical Properties. Journal of Organic Chemistry, 83(17), 10289-10302. https://doi.org/10.1021/acs.joc.8b01451

• Journal Article Type: Article
• Acceptance Date: Jun 7, 2018
• Online Publication Date: Aug 13, 2018
• Publication Date: Sep 7, 2018
• Deposit Date: Aug 15, 2018
• Publicly Available Date: Aug 13, 2019
• Journal: Journal of Organic Chemistry
• Print ISSN: 0022-3263
• Electronic ISSN: 1520-6904
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 83
• Issue: 17
• Pages: 10289-10302
• DOI: https://doi.org/10.1021/acs.joc.8b01451
• Public URL: https://durham-repository.worktribe.com/output/1351786