Synthesis, Thermal, and Spectroscopic Properties of High-Temperature Photoactive Halogen-Substituted Boron Difluoride β-Diketonate

The authors synthesized halogen-substituted aromatic β-diketone and BF₂-complex based on it. The temperatures of phase transitions and decomposition of the obtained samples are established. In contrast to the ligand with a 509.1 K (235.9°C) temperature of decomposition, the temperature stability rises to 690.3 K (417.1°C) for complexation with boron trifluoride etherate. Solutions of the complex in dichloromethane (DCM) are characterized by intense violet-blue fluorescence (QY_FL = 34%) with an emission maximum at 425 nm. This complex has green emission in the solid state, while the efficiency of solid-state fluorescence of the boron complex decreases to a 10% value of QY_FL.