Improvement of optical purity of metal tris-(1,10-phenanthroline) chelates by use of adsorption on a colloidal clay

Abstract

When the clay–metal adducts are filtered through a membrane filter from a solution containing sodium montmorillonite (3.3 × 10^–4M cation exchange sites), 3.4 × 10^–4M(+)₅₄₆-[Ni(phen)₃][ClO₄]₂, and 1.7 × 10^–4M(–)₅₄₆-[Ni(phen)₃][ClO₄]₂, the filtrate contains 1.2 × 10^–4M(+)₅₄₆-[Ni(phen)₃][ClO₄]₂ and 0.2 × 10^–4M(–)₅₄₆-[Ni(phen)₃][ClO₄]₂(phen = 1,10-phenan-throline); this improvement in optical purity results from the adsorption of the racemic metal chelate on the clay surface.