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1 Acknowledgment Synthesis and Emission Properties of Ir(III) Emitter Complexes with Different Acetylacetonate Ancillary Ligands T. Fischer 2, U. Monkowius 1, M. Zabel 2, H. Yersin 2 Introduction 1 Institut fr Anorganische Chemie, Johannes Kepler Universitt Linz, A-4040 Linz, Austria Email: uwe.monkowius@jku.at 2 Institut fr Physikalische Chemie, Universitt Regensburg, D-93053 Regensburg, Germany Email: hartmut.yersin@chemie.uni-regensburg.dehartmut.yersin@chemie.uni-regensburg.de Photophysical introduction This work was supported by the Bundesministerium fr Bildung und Forschung (BMBF). References [1] L. Deng, P. T. Furuta, S. Garon, J. Li, D. Kavulak, M. E. Thompson, J. M. J. Frchet, Chem. Mater. 2006, 18, 386; N. R. Evans, L. S. Devi, C. S. K. Mak, S. E. Watkins, S. I. Pascu, A. Khler, R. H. Friend, C. K. Williams, A. B. Holmes, J. Am. Chem. Soc. 2006, 128, 6647. [2] H. Yersin, Top. Curr. Chem. 2004, 241, 1. [3] H. Yersin, W. J. Finkenzeller, Triplet Emitters for OLEDs Basic Properties, in Highly Efficient OLEDs with Phosphorescent Materials, H. Yersin (ed.), Wiley-VCH, Weinheim, 2007. [4] A. P. Marchetti, J. C. Deaton, R. H. Young, J. Phys. Chem. A 2006, 110, 9828. Synthesis of the ligands Crystal structure of C CH 2 Cl 2 In order to minimize the phase separation within the emission layer of an OLED device the covalent linkage of the emitter compound to a polymer is the method of choice. Several examples of this strategy have been published recently.[1] Usually, in polymer-based OLEDs, the emitters are functionalized in the periphery of the molecule with polymerizable (e.g. vinyl) or other reactive groups (e.g. halogen) assuming that the luminescence properties are not altered significantly. This assumption in mind, four similar acetylacetone ligands (s-acac) and the corresponding iridium complexes (ppy) 2 Ir(s-acac) with ppy = 2-phenylpyridinate A D were prepared and characterized by proton NMR-, electronic absorption and emission spectroscopy, mass spectrometry, and by single crystal diffraction (for C). For the complexes C and D highly resolved emission and excitation spectra could be obtained at low temperature. This allows us to determine the values of zero-field splitting of the emitting triplets and thus to conclude on the 3 MLCT/ 3 LC character of the emitting states.[2, 3] A B C D Synthesis of the complexes triklinic P1, Z = 2 a = 9.9959(8) , b = 12.4521(9) , c = 14.1946(11) , a = 70.131(9), b = 82.138(9), c = 77.886(9). - Ir1-O12.143(5) O1-Ir1-O2 84.90(19)0N1-C5-C6-C11 2.0(8) Ir1-O22.143(5) N1-Ir1-N2174.1(2)N2-C16-C17-C18-3.4(8) Ir1-N12.047(6) N1-Ir1-C1180.5(3) Ir1-N22.030(6) N2-Ir1-C18 81.0(3) Ir1-C111.994(7) O1-Ir1-C11176.7(3) Ir1-C182.007(7) Silver methode: Higher yields and purer products are obtained. B (26 %) A C D (84 %) (72 %) (61 %) Complex C Complex D Site-selective spectroscopy of complex D in an n-octane Shpol`skii matrix Zero-field splittings of different (ppy) 2 Ir(s-acac)-complexes Compound E I/II [cm -1 ]E I/III [cm -1 ] I [s] (ppy) 2 Ir(acac) [4]13 a 103 b 59 a C15 a 140 a 63 a D13.5 a 118.5 a 61 a a measured in n-octane b measured in PMMA Conclusion Large zero-field splitting values for each compound indicate that the emitting triplet states are dominantly of MLCT character.[2, 3] Complexes presumably suited as emitter in OLEDs