title: Synthesis, characterization, and DFT/TD-DFT calculations of highly phosphorescent blue light-emitting anionic iridium complexes.
abstract: Highly phosphorescent blue-light-emitting anionic iridium complexes (C4H9)4N[Ir(2-phenylpyridine)2(CN)2] (1), (C4H9)4N[Ir(2-phenyl-4-dimethylaminopyridine)2(CN)2] (2), (C4H9)4N[Ir(2-(2,4-difluorophenyl)-pyridine)2(CN)2] (3), (C4H9)4N[Ir(2-(2,4-difluorophenyl)-4-dimethylaminopyridine)2(CN)2] (4), and (C4H9)4N[Ir(2-(3,5-difluorophenyl)-4-dimethylaminopyridine)2(CN)2] (5) were synthesized and characterized using NMR, UV-vis absorption, and emission spectroscopy and electrochemical methods. In these complexes color and quantum yield tuning aspects are demonstrated by modulating the ligands with substituting donor and acceptor groups on both the pyridine and phenyl moieties of 2-phenylpyridine. Complexes 1-5 display intense photoluminescence maxima in the blue region of the visible spectrum and exhibit very high phosphorescence quantum yields, in the range of 50-80%, with excited-state lifetimes of 1-4 micros in acetonitrile solution at 298 K. DFT and time dependent-DFT calculations were performed on the ground and excited states of the investigated complexes to provide insight into the structural, electronic, and optical properties of these systems.
authors.affiliation: Laboratory for Photonics and Interfaces, Station 6, Institute of Chemical Sciences and Engineering, School of basic Sciences, Swiss Federal Institute of Technology, CH-1015 Lausanne, Switzerland.
authors.forename: Davide
authors.initials: D
authors.lastname: Di Censo
authors.forename: Simona
authors.initials: S
authors.lastname: Fantacci
authors.forename: Filippo
authors.initials: F
authors.lastname: De Angelis
authors.forename: Cedric
authors.initials: C
authors.lastname: Klein
authors.forename: Nick
authors.initials: N
authors.lastname: Evans
authors.forename: K
authors.initials: K
authors.lastname: Kalyanasundaram
authors.forename: Henk J
authors.initials: HJ
authors.lastname: Bolink
authors.forename: Michael
authors.initials: M
authors.lastname: Grätzel
authors.forename: Mohammad K
authors.initials: MK
authors.lastname: Nazeeruddin