title: Faster Synthesis of Beta-Diketonate Ternary Europium Complexes: Elapsed Times & Reaction Yields.
abstract: 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 EuCl3(H2O)6, three equivalents of β-diketonate ligands to form the complexes Eu(β-diketonate)3(H2O)2. The nonionic ligands are subsequently added to form the target complexes Eu(β-diketonate)3(L)2. However, the Eu(β-diketonate)3(H2O)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(H2O)2 as an intermediate. Instead, we start by adding 4 equivalents of a monodentate nonionic ligand L straight to EuCl3(H2O)6 to form a new intermediate: EuCl3(L)4(H2O)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%.
authors.affiliation: Departamento de Química Fundamental, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil.
authors.forename: Nathalia B D
authors.initials: NB
authors.lastname: Lima
authors.affiliation: Departamento de Química Fundamental, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil.
authors.forename: Anderson I S
authors.initials: AI
authors.lastname: Silva
authors.affiliation: Departamento de Química Fundamental, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil.
authors.forename: P C
authors.initials: PC
authors.lastname: Gerson
authors.affiliation: Departamento de Química Fundamental, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil.
authors.forename: Simone M C
authors.initials: SM
authors.lastname: Gonçalves
authors.affiliation: Departamento de Química Fundamental, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil.
authors.forename: Alfredo M
authors.initials: AM
authors.lastname: Simas
mesh_terms: D005063:Europium / Q000737:chemistry*; D007659:Ketones / Q000737:chemistry*; D008024:Ligands; D049449:Luminescence; D049408:Luminescent Agents / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D007659:Ketones; D008024:Ligands; D049408:Luminescent Agents; D005063:Europium