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The title complexes displayed a marked dependence of their luminescence properties upon pyridine substitution. The ligand with the 4-carbamoyl-substituted pyridine showed a long-lived luminescence of near-unity quantum yield for Tb3- and quite reasonable values for Eu3+, Sm3+ and Dy3-, thus making it an excellent candidate for a luminescent probe to be attached to biomolecules by a peptide-like linkage.

The synthesis of novel Tb"' labels suitable for protein labelling are reported. Their luminescence properties as antibody conjugates were measured and compared to the results of corresponding Tb"' chelates of the parent ligand structures. When the lowest triplet-state energy level of the parent donor ligand was over 23 000 cm-I, i. e., the energy gap between the 5D, level of Tb"' and the lowest triplet-state energy level of the ligand exceeded 2600cm-', the label derivative with a long decay time (~=1.35-2.93 ms) and a high luminescence yield (E . 0 = 3 770-4 560) was found to be suitable for bioaffinity assays.Introduction. -Long-lifetime emitting lanthanide chelates as sensitive labels or probes, and time-resolved fluorometry in detection have already been used in a number of applications in bioaffinity assays [l].In commercial systems, due to the many requirements of optimal lanthanide chelate labels, compromises have been made, e.g., the detection comprises two separate steps, as a direct measurement of the analyte without any enhancement step is impossible [2]. In this respect, these technologies are not suitable for all applications, such as in situ hybridization, immunohistochemistry, homogeneous assays, and fluorescence imaging. In addition to sensitive bioaffinity assays, new highly luminescent and stable lanthanide labels permit the development of multilabel, miniaturized assay devices with simplified protocols and thus make it possible to perform multiparametric assays on sub-microliter volumes of samples. A lot of research effort has been directed to the design and synthesis of optimal labels also suitable for the applications mentioned above. The chelating agents commonly used for the sensitization of Eu"' and Tb"' ion luminescence include P-diketones

The hydrophilic oxygen atoms of polyethylenoxide chains inserted as pillars in gamma-zirconium phosphate form hydrogen bonds with the acid groups of the host. As a result the pillars are almost perpendicular to the gamma layers. Upon changing the pH level of the supernatant solution the hydrogen bonds are broken and the pillars become almost perpendicular to the layers (shown schematically). Thus there is a reversible enlargement-shortening of the interlayer space.

The topotactic exchange reactions of y-zirconium phosphate and y-zirconium phosphate/methylphosphonate with phosphonic acids derived from azacrown ethers of different sizes was examined. Prior intercalation of hexylamine was necessary in most cases to attain the maximum exchange level predicted by molecular modeling. Materials with imbricated or nonimbricated layers were obtained depending on crown size and exchange level. Exchange of methylphosphonates in y-zirconium phosphate/methylphosphonate was only observed when hexylamine had previously been intercalated. The exchange with the bisphosphonic acid derived from l,lO-diaza[l8]-crown-6 gave a material with an interlayer