Effects of a central element on the photoluminescence properties of β-diketiminate complexes composed of group 13 elements

Various kinds of boron complexes have been utilized as functional luminescent materials. However, only a limited number of emissive complexes containing other group 13 elements have been reported. Herein, we report the synthesis and optical properties of luminescent β-diketiminate complexes containing a series of group 13 elements. The synthesized complexes exhibited crystallization-induced emission properties. It was indicated that the heavier group 13 elements accelerate intersystem crossing from the singlet to the triplet excited state because of the strong heavy atom effect. Finally, we discovered that aluminum and gallium complexes can work as solid-state luminescent materials with high emission efficiencies.