Photophysical properties of amphiphilic porphyrins in different media

Photophysical properties (absorption spectra, fluorescence spectra, lifetimes and quantum yields) have been studied for several amphiphilic porphyrins bearing hydrophilic pyridinium and hydrophobic long-chain alkyl groups in different media. These amphiphilic porphyrins are characterized by reduced fluorescence quantum yields, aggregating appreciable in nonpolar solvents and biexponential fluorescence decay. The observed biexponential fluorescence decay of these porphyrin derivatives can be interpreted in terms of mixing of the SI and a CT state in which an electron is transferred from the porphyrin cole to the electron-deficient pyridinium group. (C) 1998 Elsevier Science Ltd. All rights reserved.