Tetrahydrodibenzophenanthridine-Based Boron-Bridged Polycyclic Aromatic Hydrocarbons: Synthesis, Structural Diversity, and Optical Properties

A series of B←N coordinated tetrahydrodibenzo­[a,i]­phenanthridine-based polycyclic aromatic hydrocarbons (PAHs) have been designed and synthesized. All of these compounds have been characterized by multinuclear NMR spectroscopy and high-resolution mass spectrometry. Compounds 1, 2, 4, and 7 have also been characterized by single-crystal X-ray diffraction analysis. Our newly synthesized compounds exhibit good luminescence quantum yields in solution and moderate quantum yields in the solid state. Furthermore, the compounds show a large Stokes shift in comparison to the well-known boron–dipyrromethene dyes.