Phosphorescence Property Modulation of <i>β</i> ‐Diketiminate Aluminum Complexes by Utilizing Intra‐ligand Charge Transfer States

Abstract We report herein synthesis and optical properties of a series of aluminum hydride complexes with various β ‐diketiminate ligands having different electronic and steric features. From the measurements, dual emission properties consisting of fluorescence and phosphorescence were observed at 77 K. In particular, it was revealed that phosphorescence from the complexes was significantly affected by the substituent effect. The theoretical calculation data suggests that the electron‐donating substituents should elevate the energy level of the T 2 state followed by the acceleration of the intersystem crossing of the S 1 –T 2 transition. These results mean that phosphorescence properties are able to be controlled by the substituent effect according to theoretical calculations without heavy atoms.