Induced Circularly Polarized Luminescence Arising from Anion or Protein Binding to Racemic Emissive Lanthanide Complexes

A circularly polarized luminescence (CPL) spectrometer has been built and used to study the binding interaction of lactate and four different proteins with racemic Eu and Tb complexes in aqueous solution. Lactate binding gives rise to strong induced CPL spectra, and the observed emission dissymmetry factors vary linearly with enantiomeric composition. Particularly strong induced Tb CPL also characterizes the binding interaction of alpha-1-acid glycoprotein with a dissociation constant, K, of 2.5 μM.