Complexation, luminescence and energy transfer in the Ce(III)– 2,2′-bipyridine complexes

Fluorescence characteristics and energy transfer to a cerium complex with 2,2′-bipyridine (bpy) in methanol are described. Stoichiometries and the stability constant of the Ce(III)–bpy complex in methanol were determined by use of the molar ratio method. A fluorescence lifetime and a quantum yield have been measured for the 2:1 complex. Decay times and time-resolved (T---S) emission spectra for Ce(III)–bpy and CeCl₃ were measured in methanol at room temperature. An energy transfer rate constant was determined from the luminescence lifetime and the quantum yield. The mechanism of energy transfer from the lowest excited singlet S₁ to the 5d level of the Ce(III) in the Ce(III)–bpy complex system is discussed in some detail.