Mono- and bi-nuclear lanthanide shift reagents and their bound displacement properties

Abstract

To facilitate better understanding of the relationship between the kind of lanthanide elements and induced shifts, a quantitative study on the behavior of various kinds of trivalent lanthanide chelate complexes on the mass spectra of butanol and acetophenone has been carried out. The lanthanides used are: La, Pr, Sm, Eu, Gd, Tb, Dy, Er, Yb. The upfield and downfield substrate ligand resonance shifts are obtained and the dependence of the observed shifts on the [lanthanide complex]/[substrate] ratio is also studied. Using mixed complexes of lanthanide chelate and silver chelate, it is possible to form binuclear complexes which cause NMR shift for olefinic compounds. Of various ligands which are used in this research, 2, ,6, 6-tetramethlheptane-3, 5-dione shows a very good shifting power for nitrogen or oxygen containing compounds, and only mixed chelate of lanthanide complex with 6, 6,7,7,8, 8, 8-heptafluoro-2,2-dimethyl octane -3,5-dione and silver chelate of 1, 1, 1-triftuoropentane-2,4-dione show olefinic sift.