EN
The equilibria between pyridine-2,6-dicarboxylate and Eu(III) in H_{2}O or D_{2}O cetyltrimethylammonium bromide micellar solutions at room temperature have been made as a function of the ligand concentration and pH by excitation spectroscopy and emission decay measurements. Formation of the tris-complex is complete at [Eu^{3+}]:[pdc^{2-}] ≥ 1:4 at neutral to slightly alkaline conditions but is incomplete under acidic conditions. The ^{5}D_{0} lifetimes corresponding to the Eu(pdc)_{3}^{3-} anion is observed to increase on association of the complex with the micellar surface due to exclusion of the solvating molecules from the second co-ordination sphere. Energy transfer in the bulk solution requires the presence of binuclear mixed Eu^{3+} and Nd(pdc)_{3}^{3-} complexes or confinement of the Ln(pdc)_{3}^{3-}/Eu^{3+} on the micelle surface. Energy transfer from the Eu(pdc)_{3}^{3-} anion is inefficient in the bulk solution.