Synthesis, structures, and photophysical properties of fluorine-functionalized yellow-emitting iridium complexes

The synthesis, structures and photophysical properties of three new luminescent cyclometalated iridium(ΙΙΙ) complexes are reported. The cyclometalated ligand used here is 2-(2-fluorophenyl)-benzothiazole (F-BT). The auxiliary ligands are acetylacetone (Hacac), 1,1,1-trifluoroacetylacetone (3F-Hacac), 1,1,1,5,5,5-hexafluor-oacetylacetone (6F-Hacac), respectively. The crystal structures of the complexes, (F-BT)2Ir(acac) (1) and (F-BT)2Ir(6F-acac) (3), show that the iridium(ΙΙΙ) ion resides in a distorted octahedral environment. All complexes exhibit bright photoluminescence (PL) at room temperature and 1 has a high solution PL quantum efficiency of 0.62. The role played by electron-withdrawing substituent fluorine on the auxiliary ligands and how the substituent influences the luminescent behaviour are discussed.