Lanthanide induced shifts in proton NMR. A statistical comparison

Repetitive lanthanide induced shift, LIS, experiments were performed with Eu(fod)[lowered 3] and Yb(fod)[lowered 3] on four rigid organic molecules, 1-adamantanol, 1-adamantanamine, 2-adamantanol and 2-adamantanamine, to determine the precision of Demarco-Wenkert and ApSimon data reduction methods. Both methods gave essentially equivalent shift parameters. The Demarco-Wenkert shift parameters, [delta] obs plotted against [L]/[S] , had 2 to 5 per cent precision. This could not be improved by replication. Greater precision, 1 per cent, was realized for ApSimon shift parameters, [delta] obs versus[summation][delta] obs. Yb(fod)[lowered 3] was found to induce downfield shifts approximately 6.4 times as large as Eu(fod)[lowered 3] in 2-adamantanamine for the same L/s ratio.