Synthetic Control of Excited-State Properties in Cyclometalated Ir(III) Complexes Using Ancillary Ligands

During the last two decades, luminescent cyclometalated Ir(III) complexes have exhibited an enormous potential for a range of photonic applications. For example, these Ir complexes can be used as emissive dopants in organic light emitting devices (OLEDs), sensitizers for outer-sphere electron-transfer reactions, photocatalysts for CO2 reduction, photooxidants and singlet oxygen sensitizers, and biological labeling reagents. Since the optical properties and related uses of the cyclometalated Ir complexes are strongly dependent on the characteristics of their ground and lowest excited states, it becomes desirable to better understand the interactions between these states and thus determine how to systematically alter the photophysical properties by appropriate ligand design.