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

An air-stable B,N-containing dibenzobisanthene (8) was prepared in 29% yield by heating a 1,3,5-tri(azasilaanthryl)benzene (5) with BBr (180 °C). Under these conditions, the reaction does not stop after threefold SiMe/BBr exchange but proceeds further two rearrangement and two intramolecular C-H borylation steps. Some mechanistic details were unveiled by using smaller model systems and applying lower reaction temperatures.

Green-Emitting Extended B,N-Doped Polycyclic Aromatic Hydrocarbon with Multiple Resonance Structure.

An air-stable B,N-PAH (; nine annulated six-membered rings) was synthesized from 1-X-2,6-di(azasilaanthryl)benzenes (X = Cl, I) via lithiation/borylation, electrophilic aromatic borylation, and Si/B exchange. The heteroatom distribution in meets the requirements for multiple resonance thermally activated delayed fluorescence (MR-TADF). Indeed, emits green light (λ = 523 nm; Φ = 85%; CHCl) with a small fwhm of 0.