Binuclear NMR Shift Reagents. An Apparent Anomalous Effect with Vinclozolin

The 60 MHz 1H NMR spectra of racemic vinclozolin, 1, have been studied at 28° in CDC13 solution with the chiral reagent tris[3-(heptafluoropropylhydroxymethylene)-d-camphorato]europium(III), 2, by incremental additions of (6,6,7,7,8,8,8-heptafluoro-2,2-di-methyl-3,5-octanedionato)silver(I), 3. Although the solution of 1 with 2 displayed substantial downfield lanthanide-induced shifts, Δδ, and enantiomeric shift differences, ΔΔδ, for selected nuclei, relative to the spectrum of unshifted 1, additions of 3 to the solution of 1 and 2 were unexpectedly found to dramatically reduce the magnitudes of both Δδ and ΔΔδ.