Chiroptical Spectroscopic Studies on Lanthanide Complexes with Valinamide Derivatives in Solution.

Ligands based on 2,2'-bipyridine and valinamide moieties induce circularly polarized luminescence in their europium complexes. Both the R and S enantiomers of the complexes were successfully obtained. Single-crystal X-ray analysis of the racemic crystal confirmed that the ligand is coordinated to the europium ion in a tetradentate fashion.

Microscopic Imaging of Chiral Amino Acids in Agar Gel through Circularly Polarized Luminescence of Eu Complex.

We recently found that [Eu(pda) ] (pda: 1,10-phenanthroline-2,9-dicarboxylic acid), which has an achiral structure in crystals, exhibits circularly polarized luminescence (CPL) in aqueous solutions containing chiral amino acids such as arginine and histidine. CPL measurements were performed for agar gel, which includes an aqueous solution of [Eu(pda) ] and chiral arginine or histidine. The spectral shape, concentration, and pH dependences on CPL intensity in the agar gels were very close to those in aqueous solutions, indicating that the CPL of the Eu complex in the agar gels was induced by mechanism similar to that in aqueous solutions.

Chiral Sensing Using Circularly Polarized Luminescence of Bis(phenanthroline dicarboxylic acid) Eu Complex Induced by Allosteric-type Interaction with Amino Acid Molecules.

[Eu(pda) ] and [Eu(bda) ] (pda=1,10-phenanthroline-2, 9-dicarboxylic acid; bda=2,2' bipyridine 5,5'-dicarboxylic acid) have an achiral D structure in crystals. These complexes exhibit circularly polarized luminescence (CPL) in water containing chiral amino acids. In this work, induced CPL of [Eu(pda) ] and [Eu(bda) ] in water solutions containing a mixture of d- and l- amino acids were examined.

Multifunctional Octamethyltetrasila[2.2]cyclophanes: Conformational Variations, Circularly Polarized Luminescence, and Organic Electroluminescence.

Both symmetrical and unsymmetrical cyclophanes containing disilane units, tetrasila[2.2]cyclophanes 1-9, were synthesized. The syn and anti conformations and the kinetics of inversion between two anti-isomers were investigated by X-ray diffraction and variable-temperature NMR analysis, respectively.