Excited-state chiral discrimination in aqueous solutions of lanthanide(III): 2,6-pyridinedicarboxylate complexes

Addition of resolved-Ru(phenanthroline)32+ to aqueous solutions of racemic complexes of Ln(2,6-pyridinedicarboxylate)33- (where Ln = Eu(III) and Tb(III) results in efficient quenching of lanthanide emission. The terbium complex is quenched more than the europium complex illustrating the importance of electronic overlap. The emission is also circularly polarized indicating that the quenching mechanism is enantioselective. Comparison with previous data allows for the identification of the enantiomer in excess, and, thus, of the favored enantioselective energy transfer pair.