TY - JOUR A1 - Pittkowski, Rebecca A1 - Strassner, Thomas T1 - Enhanced quantum yields by sterically demanding aryl-substituted β-diketonate ancillary ligands JF - Beilstein Journal of Organic Chemistry PY - 2018/// VL - 14 SP - 664 EP - 671 SN - 1860-5397 DO - 10.3762/bjoc.14.54 PB - Beilstein-Institut JA - Beilstein J. Org. Chem. UR - https://doi.org/10.3762/bjoc.14.54 KW - ancillary ligand KW - β-diketonates KW - photoluminescence KW - platinum(II) complex KW - quantum yield N2 - Luminescent organometallic platinum(II) compounds are of interest as phosphors for organic light emitting devices. Their emissive properties can be tuned by variation of the ligands or by specific electron-withdrawing or electron-donating substituents. Different ancillary ligands can have a profound impact on the emission color and emission efficiency of these complexes. We studied the influence of sterically hindered, aryl-substituted β-diketonates on the emission properties of C^C* cyclometalated complexes, employing the unsubstituted methyl-phenyl-imidazolium ligand. The quantum yield was significantly enhanced by changing the auxiliary ligand from acetylacetonate, where the corresponding platinum(II) complex shows only a very weak emission, to mesityl (mes) or duryl (dur) substituted acetylacetonates. The new complexes show very efficient emission with quantum yields >70% in the sky-blue spectral region (480 nm) and short decay times (<3 μs). ER -