A time-resolved study of the mechanism of the energy transfer from a ligand to the lanthanide(III) ion in solutions and solid films.

The photochemical properties of some lanthanide chelates developed for immunohistochemistry have been studied in water and in solid Langmuir-Blodgett films. The fluorescence and triplet-state lifetimes of 4-(phenylethynyl)pyridine (PET), di[(phenylethynyl)pyridine] (D-PET), phenylterpyridine (PTP) and their tetra- or penta-acid derivatives (-TA or -PA) were measured in the presence and absence of Gd(III)-, Tb(III)- and Eu(III)-ions. The mechanism for the total process and the rate constants and quantum yields for the individual reaction steps and for the total process were determined in water solution. Time-resolved absorption and luminescence methods were also used to study the energy transfer between an amphiphilic 4-[4-[(C(10)H(12))(2)NCO]phenylethynyl]-pyridine tetra acid (A-PET-TA) and the Tb(III)- and Eu(III)-ions in solid Langmuir-Blodgett films. Luminescence and transient absorption rate constants were determined. Copyright 2000 John Wiley & Sons, Ltd.