Recognition and sensing of chiral biological substrates via lanthanide coordination chemistry

A series of lanthanide tris(beta-diketonates) and porphyrinates was developed as effective receptors which offered chiral recognition and chirality sensing of biological substrates. These lanthanide complexes were electrically neutralized by coordinating ligands but further formed highly coordinated complexes with various substrates. We optimized the combination of coordinating ligand and lanthanide center to realize specific recognition and sensing of chiral amino alcohols and amino acids. Two further approaches were successful: (1) substitution of lanthanide tris(beta-diketonates) with chiral ligands provided efficient enantiomer-selective extraction of zwitterionic amino acids; and (2) functionalization of lanthanide porphyrinates with highly structured functions enhanced the sensitivity in CD probing of chiral amino acids. Since the lanthanide complexes have broad structural variations, the molecular recognition phenomena described here offer promising possibilities in developing a new class of chiral recognition and chirality sensing systems incorporating intelligent lanthanide complexes. (C) 2002 Elsevier Science B.V. All rights reserved.