ENERGY-TRANSFER FROM TRIPLET AROMATIC-HYDROCARBONS TO TB3+ AND EU3+ IN AQUEOUS MICELLAR SOLUTIONS

The sensitization of Tb3+and Eu3+luminescence by energy transfer from aromatic triplet donors like naphthalene, bromonaphthalene, biphenyl, and phenanthrene in micellar sodium lauryl sulfate solution has been studied. Formal second-order rate constants for the energy transfer process in the micellar solutions were determined as 5 X 105and 1.8 X 105M-1s-1for transfer from I-bromonaphthalene to Eu3+and Tb3+, respectively, and 4 X 105M-1s-1for transfer from biphenyl to Tb3+. The method of converting these rate constants to second-order constants pertaining to the micellar microenvironment is discussed; it is estimated that the transfer process at the micelles is characterized by rate constants about one order of magnitude smaller than the formal ones. The transfer process is thus extremely slow. © 1979, American Chemical Society. All rights reserved.