PHOTOPHYSICAL PROPERTIES OF AMPHIPHILIC PORPHYRINS IN DIFFERENT MEDIA

Photophysical properties (absorption spectra, fluorescence spectra, li fetimes and quantum yields) have been studied for several amphiphilic porphyrins bearing hydrophilic pyridinium and hydrophobic long-chain a lkyl groups in different media. These amphiphilic porphyrins are chara cterized by reduced fluorescence quantum yields, aggregating appreciab le in nonpolar solvents and biexponential fluorescence decay. The obse rved biexponential fluorescence decay of these porphyrin derivatives c an 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-de ficient pyridinium group. (C) 1998 Elsevier Science Ltd. All rights re served.