New yellow/orange-emitting heteroleptic iridium(III) complexes with 5,7-difluoro-2-phenylbenzothiazole ligand

Abstract

Two new phosphorescent iridium(III) complexes, (dfbt)2Ir(pic) and (dfbt)2Ir(acac) (dfbt = 5,7-difluoro-2-phenylbenzothiazole, pic = picolinate, acac = acetylacetonate), have been synthesized and characterized. Upon photoexcitation, both complexes exhibit strong yellow–orange emission in CH2Cl2 solution at room temperature with absolute quantum yields up to 99.0% and emission lifetimes up to 1.23 μs. The spectroscopic property has been calculated by density functional theory and time-dependent density functional theory, thus suggesting that the lowest absorption and the emission originate from the metal-to-ligand charge transfer/ligand-centered transition.