Highly photoluminescent Eu(III) complexes of the new 1-triphenylen-2-yl-3-trifluoroacetylacetone

The new triphenylene 1,3-diketone (1-triphenylen-2-yl-3-trifluoroacetylacetone (TphTA)) and its europium complexes were synthesized. The preliminary data on photophysical properties of Eu(TphTA)3(H2O)(C2H5OH) (1), Eu(TphTA)3(TOPO)(H2O) (2), Eu(TphTA)3(TOPO)2 (3) and Eu(TphTA)2NO3(TOPO)2 (4) are reported. Addition of a tri-n-octylphosphine oxide (TOPO) co-ligand to the europium diketonate complex removes water molecules from the coordination sphere, that leads to a significant increase of the photoluminescence quantum yield. The behavior of complexes 3 and 4 in nematic liquid crystal was investigated.

Ternary Eu(III) complex involving two 1,3-diketonate ligands, nitrate anion and two tri-n-octyl phosphinoxide co-ligands, and its photoluminescence spectrum.Figure optionsDownload as PowerPoint slideHighlights
► Tri-n-octylphosphine oxide as auxiliary ligand enhances the photoluminescence quantum yield 3-, 6-fold of the Eu(III) complex.
► The orientation of triphenylene unit is parallel to the long axis of the nematic phase.
► Nematic phases appended with Eu(III) complexes are luminescent.