Development of iridium(III)-based sensitizers for oxygen-independent phototherapy and solar energy conversion

In photochemistry, the early 2000s have marked the beginning of the success story of iridium. Thanks to their exceptional optoelectronic properties and their great photostability, iridium(III)-based compounds have emerged as promising light-emitting and light-sensitive materials. Actually, iridium(III) is characterized by the unique capacity to accommodate up to three carbometalated bonds to give mono-, bis- or tris-cyclometalated complexes. Consequently, a wide variety of spectroelectrochemical properties are available, depending on the number of Ir-C bonds formed. Nevertheless, these properties may also be fine-tuned by modifying the chemical structure of the ligands chelated onto the metal center. Herein, we report on the synthesis of a novel family of trifluoromethyl-substituted bis-cyclometalated Ir(III) complexes with an increased photo-oxidizing power. Our goal was to develop type I sensitizers for oxygen-independent anticancer phototherapy. By modifying the diimine ligand, Ir(III)-based compounds with enhanced visible light absorption have also been obtained. They were studied in order to achieve photo-induced oxidation of halides upon solar excitation. Finally, more fundamental aspects, including the investigation of the primary light-induced processes leading to the final excited state of our complexes, have also been examined.(SC - Sciences) -- UCL, 201