SOLVENT EFFECTS ON THE COMPLEXATION OF TRIVALENT LANTHANIDE CATIONS BY SUGARS AND ALDITOLS - CHROMATOGRAPHY-CALORIMETRY COMPARISON

A study of the solvent effects on the relative stabilities of the comp lexes formed between some polyols (sugars and alditols) and lanthanide cations has been performed by thin-layer ligand-exchange chromatograp hy, The R(f) values of arabinose, ribitol, ribose and glucitol in bina ry aqueous mixtures have been measured on TLC plates in the La3+ and S m3+ forms. Mixtures of water with 5 to 30 wt% Me(2)SO, acetonitrile, m ethanol, or tert-butanol were used as eluents, The modification of the polyols separation upon addition of the organic component has been ex amined, Furthermore, in order to compare the chromatographic and therm odynamic behaviours of the complexes, the stability constant for the c omplexation of Sm3+ by glucitol has been determined in the different b inary mixtures using a flow microcalorimeter. (C) 1996 Elsevier Scienc e Ltd.