Time-resolved near-IR luminescence from ytterbium and neodymium complexes of the Lehn cryptand

The Lehn cryptand has been widely applied to the study and application of luminescent lanthanide ions. We have demonstrated that the ytterbium and neodymium complexes are also luminescent. The luminescence lifetimes of the ytterbium complex fit well to established models for determining the number of inner sphere water molecules. By contrast, the neodymium complex exhibits unusually long lifetimes in aqueous media when compared to those observed with aminocarboxylate ligands. This behaviour may be ascribed to the relatively small number of proximate C–H oscillators in the cryptate.