Syntheses, spectroscopic characterization and X-ray structural studies of lanthanide complexes with adamantyl substituted 4-acylpyrazol-5-one

Synthesis and spectroscopic characterization of new lanthanide complexes [Ln(QAD)3(EtOH)(H2O)], (Ln = Tb, Eu; HQAD = 1-phenyl-3-methyl-4-adamantylcarbonyl-pyrazol-5-one), [H3O][Tb(QAD)4], [Ln(QAD)3(N–N)] (Ln = Tb, Eu; N–N = 1,10-phenanthroline (Phen), 2,2′-bipyridyl (Bipy), 4,4′-dimethyl-2,2′-bipyridyl (4,4′-Me2Bipy)) are reported. The crystal structures of the proligand HQAD and of complexes [H3O][Tb(QAD)4] and [Tb(QAD)3(4,4′-Me2Bipy)] have been determined. In both complexes the lanthanide ions are in a square antiprismatic environment, the H3O+ cation in the former acid complex being stabilized by H-bonding. Luminescence studies have been performed on selected derivatives.