501. Importance of hydrogen-bonding sites in the chiral recognition mechanism between racemic D3 terbium(III) complexes and amino acids.
- Author
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Moussa A, Pham C, Bommireddy S, and Muller G
- Subjects
- Molecular Structure, Photochemical Processes, Picolinic Acids chemistry, Pyridones chemistry, Arginine chemistry, Hydrogen Bonding, Proline chemistry, Terbium chemistry
- Abstract
The perturbation of the racemic equilibrium of luminescent D3 terbium(III) complexes with chelidamic acid (CDA), a hydroxylated derivative of 2,6-pyridine-dicarboxylic acid (DPA), by added chiral biomolecules such as L-amino acids has been studied using circularly polarized luminescence and 13C NMR spectroscopy. It is shown in this work that the chiral-induced equilibrium shift of [Tb(CDA)3](6-) by L-amino acids (i.e. L-proline or L-arginine) was largely influenced by the hydrogen-bonding networks formed between the ligand interface of racemic [Tb(CDA)3](6-) and these added chiral agents. The capping of potential hydrogen-bonding sites by acetylation in L-proline led to a approximately 100-fold drop in the induced optical activity of the [Tb(CDA)3](6-):N-acetyl-L-proline system. This result suggested that the hydrogen-bonding networks serve as the basis for further noncovalent discriminatory interactions between racemic [Tb(CDA)3](6-) and added L-amino acids.
- Published
- 2009
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