Synthesis and photoluminescence behavior of difluoroboron complexes with β-diketone ligands

[Display omitted] •Synthesis and characterization of the 4-pyridyl-β-diketones and their difluoroboron complexes.•Photoluminescence behavior of the difluoroboron complexes.•The luminescent lifetime (τ) and quantum yield (Φu) for the difluoroboron complexes. Five new difluoroboron complexes with 4-pyridyl-β-diketones were synthesized and their structures were confirmed by elemental analysis, IR, 1H NMR, ESI-MS and UV–vis spectroscopy. Their photoluminescence behavior was studied in DMF solution and solid state. The quantum yields (Φu) of complexes 2a–2e in DMF solution were measured relative to quinine sulfate and their lifetime values (τ) were calculated according to the luminescence decay curves in the solid state. From these data, the difluoroboron complexes exhibited the excellent photoluminescence properties. Especially, the complexes 2d and 2e displayed the stronger photoluminescence intensity, much higher quantum yield and longer lifetime value as compared to complexes 2a, 2b and 2c. The results indicate that the substituents at the 4-position on benzene ring have a significant impacts on the photoluminescence properties of the difluoroboron complexes.