Organoboron-based multiple-resonance emitters: synthesis, structure–property correlations, and prospects

Abstract

This review highlights organoboron-based multiple-resonance compounds’ synthetic strategies classified as one-pot borylation, one-shot borylation, and late-stage functionalisation, and explores material structure–photophysical property correlations.

Borylation and rearrangement reactions of azasilaanthracenes to afford B,N-doped nanographenes

“…Therefore, we had to use the halogenated starting materials A (X = Cl) or B (X = I) and form the first of the three B–C bonds (marked in red) via a lithiation/borylation approach. 2,13–17 Herein, we show that no C is formed in the reaction of parent 1 (X = H) with BBr 3 , because a skeletal rearrangement to the ladder-type azaborine 1 2 Br takes place instead (Scheme 2). We provide insight into some mechanistic details of this rearrangement and expand the scope of the reaction from the 1,3-disubstituted precursor 1 to its 1,3,5-trisubstituted congener 5 (Scheme 3).…”

Synthetic progress of organic thermally activated delayed fluorescence emitters via C–H activation and functionalization

“…161,162 Over the last two decades, the synthetic methodology has witnessed substantial progress, evolving into one of the most important research branches in organic synthesis. 163,164 The highly efficient and regioselective C−H borylation of aromatic substrates has been successfully established. The resulted aromatic borate esters serve as practical intermediates for subsequent Suzuki–Miyaura coupling reactions.…”

Highly efficient multi-resonance thermally activated delayed fluorescence material toward a BT.2020 deep-blue emitter

“…To overcome this drawback, we previously developed an alternative approach for designing TADF materials based on the multi-resonance (MR) effect 9 – 16 . In MR-TADF materials, the complementary resonance effects of boron 17 – 23 and nitrogen atoms realize the alternate localization of HOMOs and LUMOs at different carbon atoms on the same benzene ring.…”