SOL-GEL HOSTS DOPED WITH PORPHYRIN DERIVATIVES .11. SITE SELECTION SPECTRA AND VIBRONIC ANALYSIS

The detailed vibrational analysis of the fine structured fluorescence and excitation spectra of tetraphenylporphyrin and of tetra(pentafluor ophenyl)porphyrin embedded in polystyrene film or in inorganic or hybr id organic/inorganic sol-gel matrices under selective laser excitation at low temperature is presented. The fine structure fluorescence spec tra 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 associate d with a change in the orientation of the phenyl groups which intend t o be parallel to the macrocycle. This is in contrast with what is obse rved in polystyrene or in hybrid matrices.