Faster Synthesis of Beta-Diketonate Ternary Europium Complexes: Elapsed Times & Reaction Yields

β-diketonates are customary bidentate ligands in highly luminescent ternary europium complexes, such as Eu(β-diketonate)(3)(L)(2), where L stands for a nonionic ligand. Usually, the syntheses of these complexes start by adding, to an europium salt such as EuCl(3)(H(2)O)(6), three equivalents of β-diketonate ligands to form the complexes Eu(β-diketonate)(3)(H(2)O)(2). The nonionic ligands are subsequently added to form the target complexes Eu(β-diketonate)(3)(L)(2). However, the Eu(β-diketonate)(3)(H(2)O)(2) intermediates are frequently both difficult and slow to purify by recrystallization, a step which usually takes a long time, varying from days to several weeks, depending on the chosen β-diketonate. In this article, we advance a novel synthetic technique which does not use Eu(β-diketonate)(3)(H(2)O)(2) as an intermediate. Instead, we start by adding 4 equivalents of a monodentate nonionic ligand L straight to EuCl(3)(H(2)O)(6) to form a new intermediate: EuCl(3)(L)(4)(H(2)O)(n), with n being either 3 or 4. The advantage is that these intermediates can now be easily, quickly, and efficiently purified. The β-diketonates are then carefully added to this intermediate to form the target complexes Eu(β-diketonate)(3)(L)(2). For the cases studied, the 20-day average elapsed time reduced to 10 days for the faster synthesis, together with an improvement in the overall yield from 42% to 69%.