Intermolecular energy transfer between lanthanide complex ions in micellar solution. Part 1.—Lanthanide complexes as energy acceptors from excited Tb(pdc) 3–3 ions on cetylrimethylammonium micelles

Abstract

The ⁵D₄ luminescence decay constants for the Tb(pdc)^3–₃ ion (pdc = pyridine-2,6-dicarboxylate) in a series of aqueous solutions containing cetyltrimethylammonium micelles and Ln(pdc)^3–₃(Ln = Pr, Nd, Sm, Eu, Ho, Er) ions have been measured. Energy transfer from the Tb(pdc)^3–₃ ion to the other complex ions occurs on the surface of the micelles. The rate of the energy transfer is dependent on the equilibrium between the micellar-surface-associated and free-solution complex ions and also on the competition for sites on the micellar surface by other anions. Under optimum conditions for energy transfer the rate of the transfer is nearly three times the radiative rate constant for the Tb(pdc)^3–₃ ion. The mechanisms of the processes are discussed.