Synthesis and luminescent properties of two Schiff-base boron complexes

Schiff bases N,N′-o-phenylenebis (salicylideneimine) (H₂L¹), N,N′-p-phenylenebis (salicylideneimine) (H₂L²) and their corresponding boron complexes (BF₂)₂L¹, (BF₂)₂L² were synthesized, respectively. The two boron complexes have been characterized by ¹H NMR, mass spectrometry and elemental analysis, while the luminescent properties of them were investigated with UV-VIS spectroscopy and photoluminescence spectroscopy. Then the three-layer devices ITO/NPB (60 nm)/(BF₂)₂L¹ (50 nm)/Alq3 (20 nm)/LiF (1 nm)/Al (200 nm)] (device I) and ITO/NPB (60 nm)/(BF₂)₂L² (50 nm)/Alq3 (20 nm)/LiF (1 nm)/Al (200 nm)] (device II) were fabricated by vacuum deposition. These two devices both exhibited blue green emission at 500 nm, but showed different luminances and efficiencies.