3. Results and discussion
3.1. Structural analysis The structure of the compound [Eu2(phen)2(PFbz)6]isexpectedto
be equivalent to that of [Eu2(phen)2(bz)6], which consist of centrosymmetric dinuclear molecules in which each Eu atom is bound to one phenanthroline molecule and one terminal bidentate benzoate ligands
(Fig. 1) [31]. Additionally, the Eu atoms are linked by other four bridging perfluorobenzoate molecules, two with the carboxylate groups in the syn-syn μ-η1 :η1 bridging mode and other two benzoates with μ-η2 :η1 bridging mode. Fig. 2a shows the X-ray powder diffraction pattern of the compound [Eu2(phen)2(PFbz)6] before preparing the PPMA film so all the peaks correspond to the complex. The obtained spectrum corresponds to a polycrystalline matrix where precipitated crystals have an average diameter of 50 nm [32]. SEM analyses of Eu-complex recrystallized in CH2Cl2 are in agreement with a polycrystallinematerial, showing hexagonal thread-like crystalline structure in the range of 100 μm(Fig. 2(b)).