Salting-out thin-layer chromatography of transition metal complexes: II. Mixed aminocarboxylatocobalt(III) complexes on a polyacrylonitrile sorbent

Abstract

Fourteen mixed aminocarboxylatocobalt(III) complexes, belonging to three homologous series, were investigated by salting-out thin-layer chromatography on a polyacrylonitrile sorbent using six aqueous ammonium sulphate solutions. An increase in the salt concentration of the solvent system was found to result in a decrease in the R F values of the complexes, giving rise to a reversed-phase order. It was established that the members of a homologous series containing aminocarboxylato ligands with a straight carbon chain exhibit lower R F values than the isomeric members with branched chains. A linear dependence was found between the R M values of the complexes belonging to the same homologous series and the number of carbon atoms in their hydrophobic parts. An increase in the salt content of the solvent system causes an increase in the separation factor (α) between two adjacent members of a homologous series, and a linear dependence between log α and the concentration of ammonium sulphate was established. The separation processes described are consistent with a mechanism of non-specific hydrophobic interactions.