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Localizing Perturbations of the Racemic Equilibria Involving Dipicolinate-Derived Lanthanide(III) Complexes
Brian T Nguyen1,2, Andrew J Ingram1,3, Gilles Muller1
1Department of Chemistry, San José State University, San José, California, USA.
Abstract:
Helical D3 tris(4-amino-2,6-pyridine-dicarboxylate)terbium(III) and europium(III) complexes, which form a racemic equilibrium in aqueous solution, were prepared to study their secondary coordination sphere interactions with chiral amino acids. These interactions were probed using a combination of circularly polarized luminescence (CPL) and 13C NMR spectroscopy. The results indicate that, regardless of the interaction between the chiral molecule and the complex, without an accessible hydrogen-bond donor on the associating molecule, perturbation of the racemic equilibrium cannot occur. A generalized conclusion is established that indicates that the mechanism of chiral recognition by tris(dipicolinate)lanthanide(III) complexes is similar across a variety of analogous ligands.
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