Sol-gel hosts doped with porphyrin derivatives. Part II. Site selection spectra and vibronic analysis Original Research Article

The detailed vibrational analysis of the fine structured fluorescence and excitation spectra of tetraphenylporphyrin and of tetra(pentafluorophenyl)porphyrin embedded in polystyrene film or in inorganic or hybrid organic/inorganic sol-gel matrices under selective laser excitation at low temperature is presented. The fine structure fluorescence spectra of tetra(pentafluorophenyl)chlorin present as a contaminant in the samples have been fully analyzed. The change in the activity of some low frequency vibration modes observed in inorganic hosts is associated with a change in the orientation of the phenyl groups which intend to be parallel to the macrocycle. This is in contrast with what is observed in polystyrene or in hybrid matrices.