Covalent coupling of luminescent tris(2-thenoyltrifluoroacetonato)lanthanide(III) complexes on a Merrifield resin

Lanthanide(III) beta-diketonate complexes (Ln = Nd, Sm, Eu, Gd, Tb, Er, Yb) were immobilized on a 1,10-phenanthroline (phen)-functionalized Merrifield resin (cross-linked chloromethylated polystyrene). 1,10-Phenanthroline was coupled to the polymer beads by nucleophilic displacement of the chlorine with 5-amino-1,10-phenanthroline. Tris(2-thenoyltrifluoroacetonato)lanthanide(III) dihydrate complexes were coupled to the resin-bound 1,10-phenanthroline, and the coordinated water molecules were expelled from the first coordination sphere of the lanthanide(III) ion. Depending on the lanthanide ion, the luminescent resin beads emit in the visible region (Ln = Sm, Eu, Tb) or in the near-infrared region (Ln = Sm, Nd, Er, Yb). High-resolution luminescence spectra were recorded, and the radiative lifetimes were measured. It is shown that the spectroscopic behavior of the luminescent material is very comparable with that of the pure [Ln(tta)(3)(phen)] (tta = 2-thenoyltrifluoroacetone) complexes. The gadolinium(III) complex has been used to determine the emission behavior of the resin and ligands.