A new β-diketone complex with high color purity

In this work a new europium (III) complex with the following formula NH4[Eu(bmdm)4] was synthesized and characterized. The bmdm (butyl methoxy-dibenzoyl-methane) is a β-diketone molecule used as UV radiation absorber in sunscreen formulations. Coordination of this ligand to the Eu3+ ion was confirmed by FT-IR, while the Raman spectrum suggests the presence of NH4+ ions. The photoluminescence spectra present narrow lines arising from f–f intra-configurational transitions 5D0–7F0,1,2,3,4, dominated by the hypersensitive 5D0–7F2 transition. In the spectrum recorded at 77 K, all transitions split into 2J + 1 lines suggesting that there is just one symmetry site around Eu3+ ion. This symmetry is not centrosymmetric. The calculated intensity parameters are Ω2 = 30.5 × 10−20 cm2 and Ω4 = 5.91 × 10−20 cm2 for this complex. The CIE chromaticity coordinates (x = 0.67 and y = 0.32) show a dominant wavelength of 615 nm. The color gamut achieved by this complex is a 100% in the CIE color space.