Chromatographic Separation of Diastereomeric Schiff Base Copper(II), Nickel(II), and Zinc(II) Chelates from α-Amino Acid Racemates

Chromatographic separation of diastereomeric Schiff base copper(II), nickel(II), and zinc(II) chelates derived from optically active 3-substituted salicylaldehyde derivative and α-amino acids on a reverse-phase column was found to be successful. The separation of two elution peaks within a pair of enantiomers was excellent for most neutral amino acids. Optically pure α-amino acids were isolated from the chelates by the addition of EDTA·2Na. The formation of bis(Schiff base)metal chelates with nickel(II) or zinc(II) was discussed.