Inorganic Chemistry, Vol.34, No.22, 5615-5621, 1995
Perturbation of the Racemic Equilibrium Between D-3 Lanthanide Complexes Through the Addition of Sugars
The perturbation of the racemic equilibrium of the D-3 complexes of lanthanide (III) ions with 2,6-pyridinedicarboxylate by a number of sugars is studied by circularly polarized luminescence spectroscopy. Various spectroscopic probes show that the addition of the chiral sugar has no observable effect on the structure of the lanthanide complex. The dependence of the enantiomeric excess on the concentration of added sugar is shown to be linear for all the sugars studied. This dependence is in agreement with an equilibrium model in which the optically-active lanthanide complex forms weakly bound diastereomeric outer-sphere associated species with the various sugars. No structural correlation is found between the configuration and conformation of the sugars studied and the sign of the enantiomeric excess.
Keywords:CIRCULARLY POLARIZED LUMINESCENCE;TB(2;6-PYRIDINEDICARBOXYLATE)3(3-) LUMINESCENCE;OPTICAL-ACTIVITY;RESOLVED RU(1;10-PHENANTHROLINE)3(2+);SPECTROSCOPY