Oxygen‐Bridged Triphenylamine Units Tuning the Photophysical Properties of Classical Phosphorescent Iridium(III) Complex

Abstract

AbstractA new yellow phosphorescent iridium(III) complex Ir(ppybop)2acac with two oxygen‐bridged triphenylamine units were prepared and investigated. The cyclometalating ligand ppybop was synthesized by the efficient Suzuki‐Miyaura cross‐coupling reaction of oxygen‐bridged triarylamine unit based boron reagent 1‐a and 2‐(4‐Bromophenyl)pyridine, and the acetylacetone (acac) was used as an auxiliary ligand. Notably, the complex Ir(ppybop)2acac measured with a fluorescence spectrophotometer can show a larger redshift emission (λem=568 nm), a narrower full width at half maximum (FWHM=59 nm), a longer emission lifetime (τ[b]=3127 ns) and a better solubility in comparison with the classical green complex Ir(ppy)2acac (λem=520 nm, FWHM=70 nm, τ[b]=1206 ns). In addition, the DFT calculation results indicate that the strong electron‐donating ability of the unit can lead to the unusual ligand‐to‐metal charge transfer (3LMCT) excited state characteristics of Ir(ppybop)2acac, which is completely different from the metal‐to‐ligand charge transfer (3MLCT) in Ir(ppy)2acac. This result can provide a new strategy for the design of new phosphorescent iridium(III) complexes.