Kinetic resolution of rac-phenylalanine by stereoselective complexation to a chiral cobalt complex through pi-pi stacking interaction

Inorg Chem. 2003 Oct 6;42(20):6163-5. doi: 10.1021/ic030135g.

Abstract

A cobalt(III) complex with chiral ligand, H2cpel (N-carboxymethyl-N-pyridylethyl-l-leucine), was prepared for chiral recognition of amino acids. Through the competitive coordination of racemic phenylalanine to the chiral cobalt complex, [Co(cpel)(CO(3))](-) (1), enantioselective recognition was achieved on the ternary complex, which was determined on the basis of HPLC analysis with a chiral column. The formation rate for the [Co(cpel)(l-phe)] complex (2) was 6-times superior to that of [Co(cpel)(d-phe)] (3). The preferential formation of 2 might be illustrated by the interligand pi-pi stacking interaction. Crystal structural analysis for 2 and 3 revealed that aromatic rings, pyridine ring of CPEL and phenylalanine sidechain, in 2 were very close each other but those in 3 were far apart. Such interligand aromatic interaction in 2 was also examined by the use of (1)H NMR spectra.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cobalt / chemistry*
  • Kinetics
  • Models, Molecular
  • Molecular Structure
  • Phenylalanine / chemistry*
  • Stereoisomerism
  • X-Ray Diffraction

Substances

  • Cobalt
  • Phenylalanine