A porphyrin dye with monoexponential fluorescence intensity and anisotropy decay behavior in spherical micelles

A new fluorescent dye based on tetraphenylporphyrin contg. four di(isopropylene glycol)methyl ether groups is used as a micellar probe. The fluorescence lifetime of this porphyrin deriv. is about 10 ns, which is in the order of the rotation time of a micelle. The size of the dye (diam. ca. 37 A) ensures that it perfectly fits into most micelles. The novel fluorophore shows a monoexponential decay both in fluorescence intensity and in anisotropy in solns. of the spherical micelles. The micellar radii deduced with the help of this fluorophore are in excellent agreement with the values inferred from the scattering expts.