Syntheses, Crystal Structures, and Photoluminescence of a Series of Iridium(III) Complexes Containing the Pentafluorosulfanyl Group

Eight neutral iridium(III) complexes (Ir1–Ir8) containing an electron-withdrawing pentafluorosulfanyl (−SF5) group on cyclometalated ligands with different ancillary ligands were synthesized and investigated. 2-(3/4-(Pentafluorosulfanyl)phenyl)pyrimidine (for Ir1 and Ir2), 1-(3/4-(pentafluorosulfanyl)phenyl)isoquinoline (for Ir3 and Ir4), and 2-(3/4-(pentafluorosulfanyl)phenyl)pyridine (for Ir5–Ir8) were chosen as cyclometalated ligands and 2,2,6,6-tetramethylheptane-3,5-dione (for Ir1–Ir4), tetraphenylimidodiphosphinate (for Ir5 and Ir6), and bis(diphenylphorothioyl)amide (for Ir7 and Ir8) were used as ancillary ligands. The crystal structures of Ir1, Ir3, Ir4, Ir6, and Ir8 also confirmed the identities of these complexes. Complexes Ir1, Ir2, and Ir5–Ir8 exhibit sky blue to green emissions (480–533 nm) with high photoluminescence quantum efficiency yields up to 94.7% in CH2Cl2 solution at room temperature. Complexes Ir3 and Ir4 are red phosphors (λmax = 607 nm, Φ = 76.8% for Ir3 and λmax = 627 nm, Φ = 49.2% for Ir4, respectively). Theoretical calculations were carried out to provide a further study of the orbital distributions and electronic states of eight Ir(III) complexes. Additionally, ion detection studies reveal that Ir2 has the potential for detecting Hg2+ ion.