Phosphorescent Iridium(III) Complexes with a Dianionic C,C',N,N'-Tetradentate Ligand.

ABSTRACT

To prepare new phosphorescent iridium(III) emitters, 2-phenyl-6-(1-phenyl-1-(pyridin-2-yl)ethyl)pyridine (H2L) has been designed and its reactions with [Ir(µ-Cl)(η4-COD)]2 (1, COD = 1,5-cyclooctadiene) have been studied. The products obtained depend on the refluxing temperature of the solvent. Thus, complexes Ir(κ4-C,C',N,N'-L)Cl(CO) (2), [Ir(η4-COD)(κ2-N,N'-H2L)][IrCl2(η4-COD)] (3), and [Ir(µ-Cl)(κ4-C,C',N,N'-L)]2 (4) have been formed in 2-ethoxyethanol, propan-2-ol, and 1-phenylethanol, respectively. Complex 4 reacts with K(acac) to give the acetylacetonate derivative Ir(κ4-C,C',N,N'-L)(acac) (5). Complexes 2 and 5 are efficient blue-green and green emitters of classes [6tt+1m+2m] and [6tt+3b], respectively. They display lifetimes in the range of 1.1-4.5 µs and high quantum yields (0.54-0.87) in both PMMA films and 2-MeTHF at room temperature.