Chiral Discrimination by a Quadridentate Amine: Structural Characterization of Diastereoisomeric Complexes involving Alanine

Abstract

X-ray structure determinations have shown that two Co(III) complexes, derived from alanine and a chiral quadridentate ligand incorporating three 1R,2R-cyclohexyl moieties, both adopt Δ .-cis-β ₂ configuration. The differences between the complexes arise simply because the alanine configuration isR in one and Sin the other. Although the quadridentate is effectively stereospecific in its coordination to Co(III), bound also to a bidentate chelate, the [Co(quadridentate)] unit displays little selectivity in its binding of the amino acid enantiomers.