Luminescent lanthanide(III)-cored complexes based on the combination of 2-(5-bromothiophen)imidazo[4,5-f][1,10]phenanthroline and 2-thenoyltrifluoroacetonate ligands

A family of ternary β-diketonate lanthanide(III)-cored complexes based on the combination of 2-(5-bromothiophen)imidazo[4,5-f][1,10]phenanthroline (5-Br-TIP)/2-thiophenimidazo[4,5-f][1,10]phenanthroline (TIP) and 2-thenoyltrifluoroacetonate (TTA) ligands have been described herein, i.e. Ln(TTA)3 (5-Br-TIP) [Ln = Eu (1), Dy (2), Er (3), Tb (4), Sm (5), Yb (6)] and Eu(TTA)3(TIP) (7). According to the fluorescence spectra of complexes 1, 3, 5, 6 and 7, characteristic luminescence of the Ln3+ ions in the visible and near-infrared band ranges is observed, which is attributed to efficient energy transfer from the ligands to the metal centers. The room-temperature luminescence intensity of 7 is analogous to that of the strong fluorescent complex Eu(TTA)3(phen), but the fluorescence intensity of 1 is much weaker. In addition, complexes 1 and 7 show 1.1 and 1.4 times greater fluorescence intensity at 77 K compared with the fluorescence spectra at room temperature.

Graphical abstractA family of ternary β-diketonate lanthanide(III)-cored complexes 1–7 based on the combination of 2-(5-bromothiophen)imidazo[4,5-f][1,10]phenanthroline (5-Br-TIP)/2-thiophenimidazo[4,5-f][1,10]phenanthroline (TIP) and 2-thenoyltrifluoroacetonate (TTA) ligands have been described.Figure optionsDownload full-size imageDownload as PowerPoint slide