Paramagnetic complexes of praseodymium and europium with 1,1,l,2,2,3,3- -heptafluoro-7, 7 ~dimethyl-4,6-octanedione [Pr(fod)3 and Eu(fod)3]1 and with 2,2,6,6-tetramethyl-3,5-heptanedione [Pr(DPM)3 and Eu(DPM)3] or sometimes ab:breviated as [Pr(tmhd)3 and Eu(tmhd)3]Z--5 have shown to !be very useful NMR shift reagents which can greatly s~mplify spectra of compounds having functional gro1ups with lone pair electrons. The only other lanthanide oormplex used for this :purpose was Yb(DPM)3 6>7 • However, Yb(DPM)3 exhibited a shift power between that of Pr(DPM)3 and Eu(DPM)3 and also strong line broadening8
and therefore did not offer any substantial advantage
