Thermoreversible luminescent organogels doped with Eu(TTA)3phen complex

This manuscript details the preparation and characterization of luminescent organogels in toluene. Gels were prepared by using 12-hydroxystearic acid (12HSA) as gelator and different amounts of thenoyltrifluoroacetonato 1,10-phenanthroline europium(III) complex (Eu(TTA)3phen). The gelation properties and the thermoreversible behavior from solid-like to liquid systems were investigated by differential scanning calorimetry. At higher concentration, an interaction of Eu complex with the polar group of the gelator was revealed by DSC and FTIR analyses. The spectroscopic behavior of the complex was investigated in toluene solution and in the gel state. TEM analysis revealed that 12HSA is able to solvate the Eu diketonate complex inducing a remarkable increase in the Eu–Eu distance. The Eu(TTA)3phen in the gel state exhibits a very high emission quantum yield, Φ, which was found to be independent of Eu complex concentration, at least for the composition range analyzed. These results indicate that 12HSA organogels containing Eu(TTA)3phen are promising materials for optical applications.

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► 12HSA gels containing different amount of Eu(TTA)3phen were prepared.
► Their thermoreversible behavior from solid-like to liquid systems was investigated.
► Eu(TTA)3phen affects the intermolecular interaction in 12HSA gel.
► 12HSA solvating the Eu complex induces an increase in the Eu–Eu distance.
► Eu(TTA)3phen in gel state exhibits a very high luminescent quantum yield (Φ).