Diarenofuran[b]-fused BODIPYs: One-Pot SNAr-Suzuki Synthesis and Properties

We present a streamlined methodology that integrates regioselective tetrahalogen-BODIPY and o-hydroxyphenylboronic acid in a one-pot process, leveraging SNAr nucleophilic substitution in conjunction with Suzuki coupling to afford diarenofuran [b]-fused BODIPYs (DBFB1–9) with commendable yields (85–95%) and short reaction times (0.5–1.0 h). X-ray structure analyses of DBFB5,7–9 elucidate that these diarenofuran[b]-fused BODIPYs adopt a "butterfly" conformation, maintaining a highly rigid planarity. A comprehensive examination of the spectroscopic and electrochemical properties of these diarenofuran[b]-fused BODIPY derivatives, incorporating various substituents, reveals intriguing characteristics, including pronounced absorption and emission in the near-infrared region (NIR), elevated fluorescence quantum yields (ΦF = 75–89% in dichloromethane), and tunable HOMO–LUMO levels. Remarkably, compared to DBFB1–8, DBFB9 possesses a large extended π-conjugated system, resulting in significant red shifts in its absorption and emission maxima, reaching 623 and 635 nm, respectively, and a reduced HOMO–LUMO gap. Despite this substantial structural expansion, DBFB9 maintains a surprisingly high fluorescence quantum yield (ΦF = 80%), underscoring its exceptional photophysical performance and strong potential for applications requiring efficient NIR emission and robust fluorescence retention.