2,6-Anthracenyl(anthraquinonyl)-substituted difluoroboron dipyrromethenes: Synthesis, spectroscopy, electrochemistry and quantum chemical calculations

• A series of anthracenyl(anthraquinonyl)-substituted Bodipy dyes are synthesized.
• Moderate dihedral angles exist in anthracenyl(anthraquinonyl) and pyrrolyl plane.
• Tunable emission and electrical properties are obtained.
• ICT process is proved between Bodipy core and anthracenyl(anthraquinonyl) moiety.

A series of anthracenyl(anthraquinonyl)-substituted difluoroboron dipyrromethene dyes were synthesized through a Suzuki cross-coupling reaction. The crystal structure combined with geometric optimization reveals a moderate dihedral angle between the anthracenyl(anthraquinonyl) plane and the connected pyrrolyl plane. Photophysical characterization shows that the introduction of anthracenyl(anthraquinonyl) moiety to the BODIPY core effectively tunes the emission properties of BODIPY while retaining the separate absorption properties of BODIPY and anthracene(anthraquinone). High fluorescent quantum yields of up to 0.70 and a large Stokes shift (ca. 1707 cm−1) were noted. Electrochemical characterization suggests that the anthracenyl(anthraquinonyl) linkage and BODIPY unit lead to rich and tunable potentials. TD-DFT calculation proved a moderate intramolecular charge-transfer process between the BODIPY core and anthracenyl(anthraquinonyl) moiety.

Suzuki coupling reactions of 2,6-diiodo-8-Mesityl-1,3,5,7-tetramethyl-4,4-difluoro-4-bora-3a,4a-diaza-s-indacene and 2-anthracen(anthraquinon)-2-yl-4,4,5,5-tetramethyl-[1,3,2]dioxaborolane gave several novel core-expanded Bodipy chromophores along the long axis. Their properties were investigated by spectroscopy, electrochemistry and quantum chemical calculations, and an intramolecular charge-transfer process was proved.Figure optionsDownload as PowerPoint slide