Synthesis, structures, photoluminescent and electroluminescent properties of boron complexes with anilido-imine ligands

Syntheses of three new N-arylanilido-arylimine bidentate Schiff base type ligand precursors, ortho-C6H4[NH(2,6-iPr2C6H3)](CHNAr1) [Ar1 = p-FC6H4 (2a); C6H5 (2b); p-OMeC6H4 (2c)], and their four-coordinated boron complexes, ortho-C6H4[N(2,6-iPr2C6H3)](CHNAr1)BF2 [Ar1 = p-FC6H4 (3a); C6H5 (3b); p-OMeC6H4 (3c)] are described. The boron complexes 3a–3c were synthesized from the reaction of BF3(OEt2) with the lithium salt of their corresponding ligand. All complexes were characterized by 1H and 13C NMR spectroscopy and molecular structures of complexes 3a and 3c were determined by X-ray crystallography. The photophysical properties of complexes 3a–3c were briefly examined. All three complexes display bright green fluorescence in solution and in the solid state. Electroluminescent devices with complex 3c as the emitter were fabricated. These devices were found to give green emission with maximum current efficiency of 2.92 cd/A and maximum luminance of 670 cd/m2.