Samarium(III)−Propylenediaminetetraacetate Complex:  A Water-Soluble Chiral Shift Reagent for Use in High-Field NMR

Abstract

Samarium(III)-(R)- or (S)-propylenediaminetetraacetate complex resolved the enantiomer signals of alpha-amino acids on high-field (1)H and (13)C NMR with remarkably less line broadening than was previously reported for the Eu(III) complex of the same ligand. A widely observed regularity between the absolute configuration of enantiomers and the relative shift of their NMR signals is useful for the assignment of absolute configuration.

Chiral reagents for the determination of enantiomeric excess and absolute configuration using NMR spectroscopy

“…7) or L-aspartic acid dimethylester 66 67 and macrocyclic complexes with ligands prepared either by condensing 2,6-diformylpyridine with (R,R)-1,2-diaminocyclohexane 68 or coupling ␣-methylbenzyl amine to a nitrogen-macrocycle (15). Two reports describe the use of Sm(III) 70 and Ce(III) 71 complexes of (S)-propylenediaminetetraacetic acid as water-soluble chiral shift reagents for ␣-amino acids. The Ho(III) and Yb(III) complexes of the ␣-methylbenzylamine derivative of the macrocycle were effective for alkyl and aryl ␣-hydroxyacids.…”

Enantiomeric purity determination of acetyl-l-carnitine by NMR with chiral lanthanide shift reagents

“…Sodium [(R)-1,2-diaminopropane-N,N,N ,N -tetraacetato]samarate(III) hydrate (Sm-(R)-pdta) is known to be able to resolve the enantiomer signals of ␣-amino acids on a NMR apparatus with less signal broadening than the corresponding europium(III) complexes [10]. The structure of Sm-(R)-pdta is shown in Fig.…”

“…During the past few decades, several analytical methods, such as gas chromatography (GC), high-performance liquid chromatography (HPLC), capillary electrophoresis (CE), nuclear magnetic resonance (NMR) [3][4][5][6][7][8][9][10][11][12], etc. have been developed and successfully applied for the enantiomeric purity determination.…”

Diamagnetic lanthanide tris β‐diketonates as organic‐soluble chiral NMR shift reagents

“…In aqueous solution, one way of still utilizing chiral lanthanide ions is to use samarium(III) 4 or cerium(III) 5,6 complexes that cause the smallest shifts of all of the paramagnetic lanthanides, or to use a complex of a diamagnetic ion such as lanthanum(III). 7 Association of a donor compound with lanthanum(III) leads to complexation shifts, which occur through changes in electron shielding of the nuclei on the donor in the donor-acceptor complex.…”