Recognition of Oligosaccharides by Chirality Induced in Europium (III) Compounds

Identification of saccharides is difficult due to their similar chemical structure. However, they interact very selectively with lanthanide probes. To explore the potential for saccharide recognition, we compare circularly polarized luminescence induced by a variety of oligo- and polysaccharides in three europium compounds. Measurement on a standard Raman optical activity spectrometer made it possible to use high excitation powers and provided very distinct spectral patterns, which were sensitive both to the local structure and differences in molecular size. For example, alpha-, beta- and gamma-cyclodextrins provided unique spectroscopic responses. Titration data and molecular dynamics simulation confirmed that CPL spectra carry information about the binding mode and strength between the lanthanide probe and saccharide skeleton.