Design, Synthesis and Photophysical Studies of Luminescent Rhodium(III) Complexes in Near‐Infrared Region

Abstract

AbstractA series of near‐infrared (NIR)‐emitting cyclometalated rhodium(III) complexes have been designed, synthesized and characterized. The NIR luminescence has been realized by rational design of strong σ‐donor cyclometalating (C^N) ligand with extended π‐conjugation structure for decreasing the energy level of intraligand (IL) state. In addition, the investigation of substituents on the benzo[g]quinoxaline moiety as the carbon‐donor demonstrated that the luminescence can be further shifted to the red by the introduction of electron‐donating thienyl groups. The luminescence maxima of these complexes are ranging from 763 nm to 792 nm with the luminescence quantum yield (Φlum) of 0.41 %–0.66 % in dichloromethane solution. This work demonstrates the first example of NIR‐phosphorescent rhodium(III) complexes and provides an alternative for diversifying the development of NIR materials.