Synthesis, crystal structures and photoluminescent properties of the complexes of a new coumarin derivative with lanthanide ions

A new coumarin-based podand-type ligand (L) and its five complexes [Ln(NO3)3L] (Ln = Pr (1), Eu (2), Gd (3), Tb (4) and Er (5)) were synthesized. The X-ray single-crystal diffraction analyses indicate that these complexes are isomorphous and lanthanide ions are ten-coordinated. The tetradentate ligand forms a half-ring coordination structure with its oxygen atoms and the distances of its two chelate chains vary regularly with the ionic radii. The photoluminescence properties were also investigated by phosphorescence, quantum yields and lifetime.