Christopher M. Janks

Structure elucidation with lanthanide induced shifts. 9. bicyclo[3.3.1]nonan-9-one

Abstract Lanthanide shift reagents have been used for the conformational analysis of bicyclo[3.3.1]-nonan-9-one. Comparison of predicted shifts and experimental values obtained with Eu(fod)3 indicate that the boat-chair conformation constitutes 22% of the mixture of conformers.

Structure elucidation with lanthanide-induced shifts 5. Evaluation of the binding ability of various functional groups

The equilibrium binding constants have been evaluated for the association in CCl4 of the lanthanide shift reagent. Eu(fod)3, with a series of adamantane derivatives containing a variety of different functional groups. It is shown that if steric effects are held constant the binding abilities of the adamantane derivatives exhibit a good correlation with the proton affinities of the methyl analogs containing the same functional groups. The results permit the prediction of binding strength of other functional groups with Eu(dpm)3 as well as with Eu(fod)3 and thus can be of great assistance in planning and interpreting the results of experiments with lanthanide shift reagents.ZusammenfassungEs wurden die Gleichgewichts-Komplexbildungskonstanten für eine Reihe von Adamantanderivaten mit verschiedenen funktionellen Gruppen mit Eu(fod)3 in CCl4 bestimmt. Es wird gezeigt, daß bei Konstanthaltung sterischer Effekte die Komplex-Bindungsenergien eine gute Korrelation mit den Protonenaktivitäten der entsprechenden Methylhomologen ergibt. Die gewonnenen Resultate geben (auch für andere funktionelle Gruppen als die unmittelbar untersuchten) eine gute Möglichkeit zur Abschätzung zu erwartender Komplexbildungsstärken.

Eu(FOD)3 induced shifts of alkyl substituted adamantanones and molecular geometries of the adducts

Abstract The geometries of adducts of europium tris(fod) and a series of alkyl substituted adamantanones have been determined with the use of lanthanide induced 1H shift measurements. The position of the Eu(III) cation relative to the substrate ligand appears to be strongly dependent upon steric interactions between the fod ligands and the alkyl groups in the substrate. The alkyl substitution causes distortions from the otherwise linear C-O-Eu array. In general the Eu(III) cation moves away from the alkyl substituents.