Emission properties of ternary complexes of europium(III)-β-diketone-trioctylphosphine oxide

The effect of the substituted aromatics in RCOCH2COCF3 (R: benzoyl, 4-chlorobenzoyl, 4-methoxybenzoyl, 3,4,5-trimethoxybenzoyl, 9-anthroyl) on the emission properties of tris(β-diketonato)bis(trioctylphosphine oxide) europium-(III) complexes was investigated. The relative intensities of the sharp luminescence of the ternary europium (III) complexes in hexane at 610 nm occur in this order: 3,4,5-trimethoxybenzoyltrifluoroacetone (3,4,5-tmbtfa)>4-chlorobenzoyltrifluoroacetone (4-cbtfa)>4-methoxybenzoyltrifluoroacetone (4-mtbtfa)>benzoyltrifluoroacetone (btfa)>9-anthroyltrifluoroacetone (9-atfa). The Eu(9-atfa)3(topo)2 complex did not give the characteristic luminescence at 610 nm, but did show a broad emission in the range from 400 nm to 600 nm. Also, the solvent effect on the luminescence quantum yield (ΦL) of Eu(3,4,5-tmbtfa)3(topo)2 is described. The ternary complex shows the largest quantum yield in hexane, so the effect of the concentrations of Eu(3,4,5-tmbtfa)3(topo)2, free 3,4,5-tmbtfa and topo on the luminescence intensity, IL or ΦL values of Eu(3,4,5-tmbtfa)3(topo)2 in hexane could be investigated. (author)