Preparation and Stereoselectivity of [Cr(L‐Amino Acidato)₂(L‐Amino Acidato‐N)(H₂O)]

Abstract

New complexes of the bis‐type [Cr(AA)₂(AA‐N)(H₂O)], where AA stands for L‐amino acidato ligands (L‐leucine, L‐methionine, L‐phenylalanine, L‐serine, L‐threonine) and AA‐N represents monodentate L‐amino acidato ligand with an amino nitrogen as a donor atom, were prepared by heating mixtures of [Cr(NH₃)₆](OOCCH₃)₃ and L‐amino acid in alcoholic solution. In the case of L‐leucine and L‐phenylalanine, the mixture of (+)₅₄₆‐ and (−)₅₄₆‐[Cr(AA)₂(AA‐N)(H₂O)] were obtained. The optical resolution of the phenylalanine complex was tried by column chromatography and the (+)₅₄₆‐bis‐type complex was obtained. With the other amino acids, only (+)₅₄₆‐bis‐type complexes were stereoselectively obtained.

Keywords:

• Chromium(III) complexes
• Amino acidato complexes
• Optical isomer
• Stereoselectivity