The complexes between l-aspartic acid and metals of lanthanide series (La3+, Pr3+, Eu3+, Gd3+) have been prepared and characterized using a variety of techniques including, infrared spectroscopy, 1H NMR, 13C NMR, elemental analysis and metal contents. The sought metal effect on the electronic environment of the chiral carbon and its neighbouring atoms was observed in case of Europium and Praseodymium. The 13C downfield shift indicates a lower electron density at the carbon with consequent downfield shift observed on the α-H attached to it increasing its acidity.
International Letters of Chemistry, Physics and Astronomy (Volume 11)
M. E. Mohamed "Synthesis and Spectroscopic Characterization of l-Aspartic Acid Complexes with Metals of the Lanthanides Family", International Letters of Chemistry, Physics and Astronomy, Vol. 11, pp. 91-115, 2013