STABILIZATION OF DONOR-ACCEPTOR COMPLEXES FORMED BY ASSOCIATED PORPHYRINS IN THIN-FILMS

The tetraphenylporphine amino derivatives meso-tetra (p-aminophenyl) p orphine and meso-tetra (N,N-dihexadecyl-4-aminophenyl)porphine were in vestigated using ultraviolet and visible (UV) and infrared (IR) absorp tion spectroscopy in thin films. Porphyrins forming associated species in solution were shown to be strongly solvated. This peculiarity allo ws one to prepare thin films by solvent evaporation from solution inst ead of by crystallization of tetraphenylporphine. The appearance of a new broad band in the red and near-IR region is revealed in the UV spe ctra of both aminoporphyrins. This band is evident only in the presenc e of water traces in the thin film. The changes observed in the UV and IR spectra of meso-tetra(p-amino-phenyl) porphine thin films in the p resence of water traces, as compared with water-free thin films, are i nterpreted via the formation and stabilization of a donor-acceptor com plex in its associated form. According to the TR spectra, water molecu les participate in the formation of the solvation shell and donor-acce ptor complex.