Blue light emission from cyclometallated iridium(III) cyano complexes: Syntheses, crystal structures, and photophysical properties

• Blue phosphorescent Ir(III) dyes have been synthesized.
• The emission maxima are in the range of 440–470 nm.
• Phosphorescence quantum yields of >60% were measured.
• CIE coordinates as blue as (x, y = 0.16, 0.21) are obtained.

We describe the synthesis and crystal structures of four iridium compounds containing the 2-(4,6-difluorophenyl)pyridyl ligand. Cleavage of dichloro-bridged iridium(III) dimers with phosphorus ligands leads to (46dfppy)2Ir(L)(Cl) where L = PPh3 or P(OPh)3. Treatment of the chloro compounds with cyanide forms the cyano complexes (46dfppy)2Ir(L)(CN). All complexes exhibit a trans effect in their molecular structures due to the phosphorus ligands, with the phosphite having a greater effect than the phosphine. With L = PPh3, blue photoluminescence with CIE coordinates (x = 0.16, y = 0.24), quantum yield of 0.66 ± 0.15 and 4.5 ± 0.5 μs decay time is measured. For L = P(OPh)3, blue photoluminescence with CIE coordinates (x = 0.16, y = 0.21), quantum yield of 0.65 ± 0.15 and 2.9 ± 0.3 μs decay time is measured.

Two new blue phosphorescent iridium compounds containing the 2-(4,6-difluorophenyl)pyridyl ligand have been synthesized and characterized. Compounds 3 and 4 respectively offer CIE coordinates (x = 0.16, y = 0.24) and (x = 0.16, y = 0.21), quantum yields of 0.66 ± 0.15 and 0.65 ± 0.15, and decays of 4.5 ± 0.5 and 2.9 ± 0.3 μs.Figure optionsDownload as PowerPoint slide