Estimation of Formation Constants of Ternary Cu(II) Complexes with Mixed Amino Acid Enantiomers Based on Ligand Exchange by Capillary Electrophoresis

Abstract

Based on the principle of ligand exchange, a new method for estimating the formation constants of ternary Cu(II) complexes with mixed amino acid enantiomers has been proposed by capillary electrophoresis. As examples, the formation constants of four complexes, namely (L-OH-Pro)Cu(II)(D-Phe), (L-OH-Pro)Cu(II)(L-Phe), (L-OH-Pro)Cu(II)(D-Trp) and (L-OH-Pro)Cu(II)(L-Trp), were estimated by this method. The dependence of stability of complexes on the stereo-selectivity and the possibility of predicting the enantiomer migration order from complex stability has been discussed.