OUTER-SPHERE LIGAND-EXCHANGE CHROMATOGRAPHY ON BONDED CHIRAL SILICA-GEL

A bonded chiral phase for HPLC, obtained by reaction between a porous silica gel modified with N(aminoethylamino)propyl groups, and A(+)[Co(en)2(NO2)] Br, was prepared in order to separate optical isomers by a outer-sphere complex mechanism. The extent of the stereoselectivity of this support was tested by sampling racemates of organics acids and of tris-oxalate complexes of cobalt(III) and chromium(III). Good resolution was achieved when strong interactions of the solute (tri-oxalates complexes) with the support were involved.