Photochemistry and Photophysics of Coordination Compounds: Iridium

Mononuclear Ir(III)-polyimine complexes show outstanding luminescence properties, i.e., high intensities, lifetimes in the ¼s time range, and emission wavelengths that can be tuned so as to cover a full range of visible colors, from blue to red. We discuss the approaches for the use of ligands that afford control on luminescence features. Emphasis is placed on subfamilies of cyclometalated complexes, whose recent enormous expansion is motivated by their potential for applications, including that as phosphorescent dopants in OLEDs fabrication. The interplay of the different excited states associated with the luminescence, usually of MLCT and/or LC nature, is examined and the possible detrimental role of MC levels toward the luminescence properties is outlined. Ir(III)-polyimine moieties can be incorporated within multicomponent arrays where they can play as photoactive and/or electroactive units in photoinduced energy and electron transfer processes. The field is reviewed with attention to the processes of light collection and conversion into chemical energy.