Cyclometalated iridium(III) complexes for life science

Abstract

Photoluminescent cyclometalated iridium(III) complexes are now a well established class of organometallic compounds with advantageous potential applications in biology and life science. While these complexes, along with other luminescent transition metals and lanthanoid complexes, were initially proposed as alternative markers to organic fluorophores in the staining of cells, it is now evident that their specific biological behavior makes this class of compounds useful in broader areas of life science such as imaging, sensing and therapy. The critical factors for the effective design of cyclometalated iridium(III) complexes with specific biological properties are still rather difficult to rationalize, and often mainly rely of aspects such as the intrinsic charge of the complex, its lipophilicity and its aqueous solubility. This review overviews the area of cyclometalated iridium(III) complexes in biology, with an emphasis on comparing the various conditions that these compounds have been assessed for their biological potential, such as the specific tested cells lines, concentration of internalization, incubation time, and mechanism of cellular entrance.