DYNAMICS IN EXCITED-STATE CHIRALITY - STUDIES IN EXCITED-STATE RACEMIZATION AND CHIRAL RECOGNITION IN LANTHANIDE AND TRANSITION-METAL COMPLEXES

Time-resolved chiroptical luminescence measurements can be used to monitor dynamic changes in excited-state enantiomeric excess of chiral lanthanide species in solution. This paper reviews work done in our laboratories studying excited-state dynamics of chiral populations caused by interconversions of enantiomers (racemization) and enantioselective quenching of a racemic, chiral excited-state population by a resolved, chiral quencher population. The lanthanide luminophores used in these studies are aqueous solutions of tris(2,6-pyridinedicarboxylate)Ln(III) complexes (Ln(III) = Eu(III) or Tb(III)). The processes represent intramolecular structural interconversions (racemization) and intermolecular chiral discrimination.