INFLUENCE OF WATER ON SPECTRAL PROPERTIES OF PORPHYRIN ASSOCIATES IN THIN-FILMS

The influence of water on the properties of the tetraphenylporphine am ino derivatives meso-tetra(p-aminophenyl)porphine and meso-tetra(N,N-d ihexadecyl-4-aminophenyl)porphine was investigated in thin films by ab sorption, infrared (IR), and fluorescence spectroscopy. According to t he absorption spectra, the structure of the electronic transitions of the associated porphyrins in water-free thin films remains similar to that of the porphyrins in solution. However, a new low-energy excited state, lower than the Q(x) electronic transition, is revealed by the a bsorption and fluorescence spectra in thin films of tetra(p-aminopheny l)porphine in the presence of traces of water. As indicated by the IR spectra, the water molecules participate in the formation of a solvati on shell in the thin films and are directly involved in the structure of the intermolecular complexes of both porphyrins.