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 P-diketone molecule used as UV radiation absorber in sunscreen formulations. Coordination of this ligand to the Eu3+ ion was confinned 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 (D0-F0,1,2,3,4)-D-5-F-7, dominated by the hypersensitive D-5(0)-F-7(2) 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 ohm(2) = 30.5 x 10(-20) cm(2) and ohm(4) = 5.91 x 10(-20) cm(2) 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. (c) 2005 Elsevier B.V. All rights reserved.