Optical resolution of DL-amino acids by ligand exchange : I. a study of the resolution of DL-aspartic acid with the aid of copper complexes of L(a)-alanine

Spectrophotometric studies were made of the reaction of the Cu complexes of L-alanine with DL-aspartic acid to give a ppt. of a Cu-D-aspartic acid complex, and the effects of stirring, addn. of NaClO4 as supporting electrolyte, pH, and temp. on the quantity of the complex pptd. were detd. Both L- and D-aspartic acid react with the Cu-L-alanine complex, and the Cu-D-aspartic acid complex pptd. is nonstoichiometric with no evidence of Cu-Cu bonds. After pptn. of the Cu-D-aspartic acid complex, a Cu-L-aspartic acid complex is pptd. Resoln. occurs only between pH 2.7 and 5.3, and the specificity of resoln. is detd. by kinetics rather than by thermodynamics. [on SciFinder (R)]