Synthesis and photophysical properties of BN-benzo[b]triphenylene

We report a novel synthetic route of BN-benzo[b]triphenylene (BNBT) with a key-step yield exceeding 90% based on simple raw materials. The solvent effect on the optical absorption and fluorescence of BNBT is examined, and a linear relationship between the Stokes shift (ΔνS) and the solvent parameters {α, β, π*} is generalized. The fluorescence lifetime correlates positively with the fluorescence quantum yield, which is about 10 folds of benzo[b]triphenylene (BT) as a structural counterpart (66% vs 6%). Moreover, the quantum yield of triplet-excited state BNBT is shown to be as low as a few thousandths.