Analysis of the temperature dependence of the racemization of Eu(III) complexes through measurement of steady-state circularly polarized luminescence

The temperature dependence of the steady-state luminescence dissymmetry rat io, g(lum), has been measured for racemic Eu(III) complexes containing the terdentate ligands dipicolinate and phenylethynyl-dipicolinate. As the temp erature is increased, the magnitude of the dissymmetry ratio for these spec ies decreases due to racemization occurring during the excited state lifeti me. The temperature dependence of g(lum) is analyzed by a non-linear curve- fitting technique to determine the activation energies for the interconvers ion of the enantiomers. Comparison is made with previous measurements invol ving time-resolved circularly polarized luminescence. (C) 2000 Elsevier Sci ence B.V. All rights reserved.