Salting-out thin-layer chromatography of transition metal complexes. I. Investigation of the behaviour of mixed aminocarboxylato cobalt(III) complexes on silica gel

Abstract

Twenty-four mixed aminocarboxylato cobalt(III) complexes of anionic and neutral types, containing nitro ligands with or without ammonia ligands and belonging to six homologous series, were investigated by salting-out thin-layer chromatography on silica gel, using seven ammonium sulphate solutions in water. In most cases it was established that a decrease in the RF values of the complexes accompanied increasing salt concentration of the solvent systems used. A positive linear dependence between the RM [log (1/RF - 1)] values of the complexes and the mol percent (mol fraction × 100) of ammonium sulphate in the solvent systems used was found. Finally, a positive linear dependence between the RM values of the complexes of a homologous series and the number of carbon atoms in the hydrophobic part of a complex was also established. To explain these results, a mechanism based on hydrophobic interaction between the sorbate and the sorbent is proposed. © 1992.