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-III and Tb-III 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-III CPL also characterizes the binding interaction of alpha-1-acid glycoprotein with a dissociation constant, K-d, of 2.5 mu M.