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 l uminescent lanthanide ions. We have demonstrated that the ytterbium and neo dymium complexes are also luminescent. The luminescence lifetimes of the yt terbium complex fit well to established models for determining the number o f 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 relati vely small number of proximate C-H oscillators in the cryptate. (C) 2001 El sevier Science B.V. All rights reserved.