Effect of electronegativity of donor atoms on RF values of tris(β-diketonato) complexes of cobalt(III), chromium(III) and ruthenium(III) by thin-layer chromatography on silica gel

The effect of the electronegativity of donor atoms on RF values obtained by TLC on silica gel was investigated with two series of complexes of the type [M(acac)3-n(phacphac)n] and [M(acac)3-n(phacphSac)n], where M is Co(III), Cr(III) or Ru(III), acac=2,4-pentandionato ion, phacphac=1,3-diphenyl-1,3-propanedionato ion and phacphSac=3-mercapto-1,3-diphenyl-prop-2-en-1-on ion (n=0-3). Development was with nine single and six two-component solvent systems. The RF values of the complexes increase by replacing one oxygen atom of a β-diketonato ligand with a less electronegative sulphur atom. A positive linear dependence between the RM values of the complexes and the numbers of acac substituted by phacphSac ligands was established. The separation mechanisms and separation factors are discussed. © 1993 Friedr. Vieweg & Sohn Verlagsgesellschaft mbH