Development of unsymmetrical boron complexes bearing (iso)quinolylphenol ligands and their halogenated derivatives; crystal polymorphism for white-light-emitting properties

Abstract

Boron complexes bearing (iso)quinolylphenol ligands and their halogenated derivatives were synthesized to investigate their optical properties. The structural effects of the (iso)quinoline rings and halogenated positions on the photoabsorption and fluorescence emission properties of the complexes were observed in both solution and the solid state. In particular, chlorination at the C5 position of the phenol moiety induced crystal polymorphism. This resulted in unique dual emission bands in the solid state, resulting in white-light-emitting properties. The relationship between the emission properties and molecular structures was investigated in detail using X-ray crystallographic and powder X-ray diffraction analyses.