Synthesis and Fluorescence Properties of Novel Pyrazine–Boron Complexes Bearing a β-Iminoketone Ligand

A novel fluorescence dye based on pyrazine–boron complexes bearing a β-iminoketone ligand has been synthesized by using a simple two-step reaction. Synthesized complexes exhibited fluorescence in solution (F_max: 472–604 nm) and in the solid state (F_max: 496–624 nm). These complexes showed a larger Stokes shift (3690–4900 cm^–1) than well-known boron dipyrromethene dyes (400–600 cm^–1, in most cases).