Tuning the Emission Color of Iridium(III) Complexes with Ancillary Ligands: A Combined Experimental and Theoretical Study

• Published in: European Journal of Inorganic Chemistry 2009-06, Vol.2009 (16), p.2407-2414
• Main Authors: Gu, Xin, Fei, Teng, Zhang, Houyu, Xu, Hai, Yang, Bing, Ma, Yuguang, Liu, Xiaodong
• Format: Article
• Language: English
• Subjects: Charge transfer; Density functional calculations; Dyes/Pigments; Iridium; Ligand effects
• ISSN: 1434-1948; 1099-0682
• DOI: 10.1002/ejic.200801185

A series of iridium(III) complexes [Ir(dfppy)2(LX)] {dfppy = 2‐(2,4‐difluorophenyl)pyridine, LX = acac, FIr(acac); dbm, FIr(dbm); natfac, FIr(natfac); acac = acetylacetonate, dbm = dibenzoylmethanane, natfac = 1‐naphthoyl‐3,3,3‐trifluoroacetone} have been synthesized and characterized by elemental analysis, NMR and IR spectroscopy, and mass spectrometry. The cyclic voltammetric, absorption, and emission properties of these complexes have been systematically investigated. Density functional theory (DFT) and time‐dependent DFT (TD‐DFT) calculations have been performed to investigate the ground‐ and excited‐state properties of these complexes to provide an insight into their structural, electronic, and optical properties. The results of this work provide further evidence regarding how and to what extent the substituents on the ancillary ligand LX influence the emission properties of [Ir(dfppy)2(LX)] complexes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) Color tuning of iridium(III) complexes is achieved by attaching electron‐donating or electron‐withdrawing substituents to the ancillary ligand LX. The calculated results show that the low‐lying excitations have MLCT and ILCT character. For the emission process, the main transition ofFIr(acac) is [d(Ir) + π(CN) → π*(CN)] and those of FIr(dbm) and FIr(natfac) are [d(Ir) + π(LX) → π*(LX)].