Hydrothermal synthesis, crystal structures and photoluminescence properties of mixed europium-yttrium organic frameworks

Three mixed europium-yttrium organic frameworks: Eu_2-xY_x(Mel)(H₂O)₆ (Mel=mellitic acid or benzene-1,2,3,4,5,6-hexacarboxylic acid, x=0.38 1, 0.74 2, and 0.86 3) have been synthesized and characterized. All the compounds contain a 3-D net with (4, 8)-flu topology. The study indicates that the photoluminescence properties are effectively affected by the different ratios of europium and yttrium ions, the quantum efficiency is increased and the Eu³⁺ lifetime becomes longer in these MOFs than those of the Eu analog.