Near-Infrared Phosphorescent Iridium(III) Benzonorrole Complexes Possessing Pyridine-based Axial Ligands

Novel
near-infrared phosphorescent iridium­(III) complexes based on benzo-annulated
N-linked corrole analogue (termed as benzonorrole) were synthesized.
The structures of the complexes revealed octahedral coordination geometries
involving an organometallic iridium–carbon bond with two external
axial ligands. Interestingly, the iridium­(III) complex exhibits near-infrared
phosphorescence at room temperature at wavelengths beyond 900 nm.
The significant redshift of the emission, as compared to the corrole
congener, is originated from the ligand-centered triplet character.
The fine-tuning of the photophysical properties of the complexes was
achieved by introducing electron-donating and electron-withdrawing
substituents on the axial pyridine ligands.