New Methods for the Synthesis of Highly Fluorescently Substituted Heterocyclic Boranils: Structural Identification and Photophysical Properties

We report the synthesis, structural, thermal, and photophysical properties of six boranils ((A-F)-BF2). Compounds (A-C)-BF2 were synthesized at low temperature, while nitro and pyridine derivatives were obtained at 80°C with yields up to 66%. Tert-butyl and chloro-substituted boranils showed thermal stability up to 300 °C. All boranils were fluorescent, with properties tuned by phenyl substitution and boron difluoride complexation. The lowest energetic gap (2.210 eV) was found in (D-BF2), which exhibited a remarkable red-shift in absorption and emission due to charge transfer between donor and acceptor groups. This work is part of ongoing studies on metal cation detection and photocatalysis.