Lanthanide shift reagents for nuclear magnetic resonance spectroscopy

Evidence for Substrate Binding by the Lanthanide Centers in [Li3(thf)n(binolate)3Ln]: Solution and Solid‐State Characterization of Seven‐ and Eight‐Coordinate [Li3(sol)n(binolate)3Ln(S)m] Adducts

“…Paramagnetic complexes provide greater chemical-shift dispersions than their diamagnetic counterparts, thereby allowing the study of normally unobservable metal-substrate interactions. [10] Previously reported 1 H NMR spectroscopic binding studies of [Na 3 A C H T U N G T R E N N U N G (thf) 6 A C H T U N G T R E N N U N G (binolate) 3 Pr] and [Na 3 A C H T U N G T R E N N U N G (thf) 6 -A C H T U N G T R E N N U N G (binolate) 3 Eu] with cyclohexenone showed small chemicalshift differences for the a-vinyl proton of 0.1 and 0 ppm, respectively. [8] Similarly, addition of pivalaldehyde to 6 A C H T U N G T R E N N U N G (binolate) 3 Pr] resulted in a shift of the signal for the formyl hydrogen atom of only 0.1 ppm.…”

Nuclear Magnetic Resonance Studies. XXVII. Homoenolization of Fenchone. A Mechanistic Study Utilizing C And H Nuclear Magnetic Resonance

“…scale, for observations at the same magnetic field (16), the shift range for 'H nuclei is reduced by a factor of 6.5 because of the lower magnetogyric ratio and the spectra of compounds containing similar but nonequivalent 'H nuclei may have heavily overlapping signals. In many cases, this inconvenience may be reduced through the use of lanthanide shift reagents to obtain greater shift dispersion (17). Even with overlapping signals, however, precise integrated intensities may be obtained by computer line-shape fitting rather than the usual electronic integration.…”

New synthesis of mephenoxalone

“…Lanthanide reagents are frequently used in organic synthesis as catalysts in different reactions, [17][18][19][20][21][22] but lanthanide camphorates are typically used as chiral shift reagents for direct determination enantiomeric compositions by nuclear magnetic resonance. [23][24][25] Here, europium and ytterbium camphorates were used to establish their catalytic capacity and asymmetric induction in the addition of TMSCN to the carbonyl group. They generated excellent activation in both cases, 96% and 88% yield respectively, but asymmetric induction was not observed.…”